Housing Numbers

Guildford Borough Council’s paper “How many new homes?” sets out to provide a range of different approaches to calculating housing numbers between 2011 and 2031.  The resulting picture is a potentially confusing one with estimates of NEED ranging from 181 homes per year to 1,066 new households per year.  This seems to be akin to a game of ‘pin the tail on the donkey’ – a blindfold stab in the dark.

Before going on to the paper itself, it might be helpful to review the requirement placed on us by the National Planning Policy Framework (NPPF) 2012.

NPPF (Section 6) Delivering a wide choice of high quality homes

47. To boost significantly the supply of housing, local planning authorities should:

  • use their evidence base to ensure that their Local Plan meets the full, objectively assessed needs for market and affordable housing in the housing market area, as far as is consistent with the policies set out in this Framework, including identifying key sites which are critical to the delivery of the housing strategy over the plan period;
  • identify and update annually a supply of specific deliverable sites sufficient to provide five years worth of housing against their housing requirements with an additional buffer of 5% (moved forward from later in the plan period) to ensure choice and competition in the market for land. Where there has been a record of persistent under delivery of housing, local planning authorities should increase the buffer to 20% (moved forward from later in the plan period) to provide a realistic prospect of achieving the planned supply and to ensure choice and competition in the market for land;
  • identify a supply of specific, developable12 sites or broad locations for 

    growth, for years 6-10 and, where possible, for years 11-15;

  • for market and affordable housing, illustrate the expected rate of housing delivery through a housing trajectory for the plan period and set out a housing implementation strategy for the full range of housing describing how they will maintain delivery of a five-year supply of housing land to meet their housing target; and
  • set out their own approach to housing density to reflect local circumstances.

My first question, therefore, is “WHAT IS OUR HOUSING AREA?”. Previous attempts to assess housing numbers have had Guildford and Waverley as the Strategic Housing Market. Given the expectation that Ash South and Tongham will take a substantial amount of development, it must, surely be relevant to consider Aldershot as part of our Strategic Housing Market.   In the absence of a new SHMA (Strategic Housing Market Assessment) it seems Guildford Borough Council is asking us to consider the Borough as our Strategic Housing Market.  This seems to me to be not only the wrong answer but inherently dangerous to our settlements and environment.

Perhaps the table used elsewhere in the Evidence Base (reproduced below) based on the 2001 Census – due to be updated when 2011 Census data is published in Spring 2014 – would show the wider Strategic Housing Market as it impacts on Guildford and vice versa.


My second question is about NEED – how should this be defined, because it ought not to be confused for DEMAND;

And my third question is about CAPACITY – this is not the document to explore our capacity to accommodate housing BUT it is a salient point in order to be realistic.  Guildford Borough Council themselves within this document make comments against some of the scenarios: “We consider this housing number to be unachievable in the borough.”  It seems, therefore, appropriate to have some regard in reviewing this paper to CAPACITY.  The Evidence Base has not really explored CAPACITY in absolute terms, leaving us to guess what development we can absorb.  This paper introduces real fear in the absence of a statement of capacity (notwithstanding that changes to Green Belt and Infrastructure could change that number (let’s call that ‘CONDITIONAL CAPACITY’).

John Baylis (Guildford Society Planning Group) has drafted an excellent commentary – for which I am grateful and which I set out below.  I have added my comments in blue where I believe there is either question or scope for further discussion of the document itself (rather than the issues it brings forward.

The GBC Background Paper ‘How Many New Homes?’ October 2013



A note prepared by John Baylis for the Guildford Society

‘How Many New Homes?’ is a GBC background paper, which will inform selection of the housing number in the new Local Plan.


The paper considers eleven options. They are set out in the paper’s Executive Summary and look at the future need for homes between 2011 and 2031. Quoting from the Executive Summary, the options are:

Official CLG numbers

1:   14,071 homes (an average of 704 a year) [an increase of 27.24% over the plan period above current (54,000) households]. This housing number is based on the government’s 2011 projections for household growth.

2:   8,300 to 9,480 homes (an average of between 415 and 474 a year) [15.37 to 17.56%]. This housing number is based on the government’s 2010 projections for household growth.

Migration-trend based housing numbers

3:   11,820 to 13,480 homes (an average of between 591 and 674 a year) [21.89 to 24.96%]. This housing number is based on a modified version of migration trends over the last five to ten years.

4:    3,620 to 4,520 homes (an average of 181 to 226 a year) [6.70 to 8.37%]. This housing number is based on an assumption that only the same number of people would move into Guildford borough as move out of the borough.

Jobs-led housing numbers

5:    7,160 to 8,520 homes (an average of 358 to 426 a year) [13.26 to 15.78%]. This housing number is based on the calculation, by Experian in spring 2010, of the number of new jobs that are likely to be created in the borough.

6:    11,440 to 13,100 homes (an average of 572 to 655 a year) [21.19 to 24.26%]. This housing number is based on the calculation, by the Institute of Employment Research (IER) in 2007, of the number of new jobs that are likely to be created in the borough.

7:     9,280 to 10,800 homes (an average of 464 to 540 a year) [17.19 to 20.00%]. This housing number is based on an average of the Experian and IER data for the number of new jobs that are likely to be created in the borough.

Dwelling-led housing numbers

8:    6,864 homes (an average of 312 a year) 12.71%]. This housing number is based on the number of homes that have actually been built in Guildford borough in the last 13 years.

9:     7,084 homes (an average of 322 a year) [13.12%]. The draft South East Plan proposed a lower housing number for Guildford borough than the final version of the plan. This housing number is the same as the one in that draft plan.

10:    21,320 homes (an average of 1,066 a year) [39.48%]. This housing number is based on a housing needs assessment model for meeting all of our existing and forecasted future need for affordable homes in the borough to 2031.

11:    14,168 homes (an average of 644 a year) [26.24%]. This housing number would meet about half of our existing and forecasted future need for affordable homes in the borough to 2031. The number is based on a model, which looks at how much supply and demand are balanced across the different tenures and property sizes.

Thus the projected numbers of homes needed in the future range from 181 to 226 new homes a year (based on hypothetical zero net migration) to 1,066 homes a year (meeting the entire SHMA affordable homes need figure).

The Council employed a specialist firm, Edge Analytics to assist with and to critically review the above findings. The second half of the paper comprises their report.

The paper notes that National government policy tells us we must plan for growth.


The borough had a population of just over 137,000 people in 2011, (Census 2011), an increase of 5.8 per cent from 2001 (0.6% per year).  The 2011 Census shows that there were just under 54,000 households in the borough.

There is a need for more affordable homes. As of 31 March 2013 there were 2,090 priority households on the Council’s housing waiting list (those in bands A-C, which are the highest priority of the five waiting list bands). [Based on a provision of 35% Affordable Houses from all housing development, this would assume 5,975 houses (an 11.06% increase in current housing stock) would have to be built just to provide for the 2,091 priority households]

From 2009 to 2031, the population projection data suggests the number of people aged 60 or over will increase from 28,300 to 38,700. For this and other reasons the number of people who will live alone in our borough will increase. In 1991, the number of single-person households made up 25 per cent of all households. By 2031, the data suggests that these households will account for 39 per cent. Past trends suggested household sizes were decreasing, but the recent Census in 2011 has surprisingly shown that household sizes have increased from 2001. [This may show the difference between NEED and DEMAND – for example, if we had more homes for single people, perhaps we would have filled them, maintaining the 2001 level; as it happens, we did not provide them and so people made other arrangements]

Over the six years 2007 to 2012 there have been about 1,630 births and 1,000 deaths in the borough each year, giving a ‘natural change’ of about 630 per year (0.46% per year) [at 2.43 people per household (current average) this equates to around 260 houses per year].

Over this same period the average net internal migration has been close to zero, about 15 per year, i.e. over the five years the total immigration from the rest of the UK has exceeded the total emigration by only about 70.

In 2001/02 immigration and emigration were equal at about 2,000. Over the three years 2009/12 the average immigration was about 3,500 and emigration 1,600, giving a net international migration of about 1,900 per year (about 1.4%) [about 782 homes per year]. This is far greater than the natural change and net internal migration figures above. The paper remarks that “International migration is estimated to have had the most significant impact upon population in recent years. This has been driven by both an estimated increase in immigration and a decline in the level of emigration (figure 6). The robustness of this trend is important as it can have a very significant impact on any trend projection that is developed for the Borough.”

The paper then goes on to predict the future net international immigration, and concludes it is has recently been around 0.14% and will fall to a steady 0.06% over the period up to 2031. There is no comment on the gross disparity of the 0.14% figure (source What homes where? tool) and the above 1.4% figure (source Edge Analytics July 2013). What homes where? predicts close to zero net internal immigration.

Total population change is the sum of natural change, and net internal and international immigration.

In the context of Option 1 above the paper then looks at total population predictions for the Borough. Fig 13 of the paper gives three very different prediction curves each based on different ONS statistics. The most likely curve would seem to be the ‘2008 – based’ curve predicting 153,000 by 2031, about 800 per year [equivalent to around 330 homes per year], about 0.6%. This is in accord with the present 0.46% natural change plus the 0.14% net international immigration, i.e. in accord with previous growth.

However the ONS gave a ‘2011 – interim prediction’ which predicts much more rapid growth, to about 156,000 by 2021 (see blue curve of Fig 13.) The curve gives 1.4% average growth per year and thus does not accord with previous growth. The government used this to predict household growth rates to 2021 and the Council have extrapolated this to give 68,251 households by 2031, a rise of 14,071. [at 2.43 people per household, this should equate to 64,198 households (4,053 fewer homes)]


1. The 14,071 number comes directly from the above. The paper says “we consider this number to be unachievable”, comments on the unreliability of the number and notes that the government will produce revised predictions in mid-2014.

2. Edge Analytics used another ONS forecast, the ‘SNPP-2010’, which they argue to be more reliable, and adjusted it to accord with the 2011 census. It gives a net population growth of about 0.65% per year. This gives the range 8,300 to 9,840 new homes. The two different figures reflect predictions based on 2011 and 2008 statistics and account for the rise in average household sizes over this period (from 2.37 to 2.43). Larger households lead to a need for fewer homes.

3.  The prediction of 11,820 to 13,480 homes is based on net international immigration figures produced by the Office of National Statistics (ONS) for the five years to 2011, but with modification to the ONS long term assumptions. The predicted population growth is 21%, 1.05% per year, which is high compared with option 2.

4.  This prediction gives 3,620 to 4,520 homes, the lowest of any of the predictions. The paper comments that zero net migration is not the same as only providing for the needs of local people, as it takes into account movement of people in and out of the borough. The prediction is considered to be unrealistc.

5 and 6. The predictions are based on Edge Analysis modelling of the needs arising from the shortfalls in labour predicted by Experian and the IER over the period 2008 to 2031.

7. This projection uses employment projection data from the Council’s Employment Land Assessment (ELA).

Experian IER GBC ELA
Growth in employment :            7,825 (0.4% per year) 16,540 (0.9% per year) 12,165 (0.6% p.y.)
Growth in active labour supply:4,100 (0.25% per year) 4,100 (0.25% per year)  4,100 (0.25% p.y.)
Shortfall:                                        3,725 12,440  8,065
Pre-existing shortfall in 2008:  13,037 12,447 12,291
Shortfall in 2031:                        16,762 24,887 20,356

The majority of the housing needs arise from the existing shortfall.

8. The average new number of homes built over the period 2000/01 to 2012/13 is 312 per year. In the five years 2008/09 to 2012/13 this fell to an average of 207 per year.


9. The submission draft South East Plan (2006) allocated Guildford borough 322 homes a year. The Council supported this number, subject to caveats regarding infrastructure provision and the protection of key areas of nature conservation. The majority of local people who responded to the South East Plan public consultation that ran in 2006 also supported this number. It originated in the Surrey Structure Plan of 2004 and is in accord with historic building rates.

The final SEP demanded 422 homes a year. This led to massive local objection during 2008 and 2009, supported by Councillors and our local MP Anne Milton. There were over 4,800 representations. The campaign’s slogan was ‘Don’t Wreck Guildford’.

10. The prediction of 1,066 homes per year comes from the West Surrey Strategic Housing Market Assessment (SHMA) produced as a result of co-operation between GBC and Waverley and published in 2009. Between 2011 to 2031 the estimated need will be 1,194 x 5 years to overcome the present backlog plus 1,028 x 15 years = 21,320 homes, which gives 1,066 a year. Council considers this housing number unrealistic for several reasons. [As noted above, it seems illogical to conclude that Guildford’s market is merely Guildford and Waverley – it should definitely include Rushmoor to make sense of the heralded large-scale expansion of Ash South and Tongham]

11. This housing number also came from the SHMA. The number is based on a model, which looks at how supply and demand are balanced across the different tenures and property sizes. It would mean building 12,880 homes between 2011 and 2031, an average of 644 new homes a year. The Council considers this housing number unrealistic.

The predictions of the eleven options are displayed in a histogram in Fig 18, p 34 of the paper:



The Edge Analytics report gives more detail concerning the factors taken into account in arriving at the predictions. It emphasizes that it is important to recognise the high degree of uncertainty associated with evidence on international migration, particularly the recent estimates of emigration from Guildford Borough.

The report gives a brief outline of their POPGROUP model used for modelling and prediction.

At the end it says it has used a commuting ratio of 0.974 as the balance between the size of the resident labour force and the number of jobs available in Guildford. The meaning of this number is not clear. The total employment in the Borough is given as about 83,000 in Options 5 to 7, and the 2008 shortfall as around 12,000, equivalent ratio about 0.85.

The report does not attempt to do the sum the other way round. For given assumptions and build rates of new homes it should be possible to estimate what the effects will be on population, employment and immigration.

The report demonstrates the significant effects of the two different CLG household projection model assumptions used: Scenario A (2011 based) and Senario B (2008 based). These reflect the rise in household size.

The report has some useful summary tables. A combined summary table is given at the end of this note.


The starting point for debate on numbers is surely the draft SEP figure of 322 per year. Indeed the Council’s Executive agreed to use 322 homes a year as the borough’s interim housing number, until a local housing number is adopted as part of the new Local Plan.

This number was vigorously defended by nearly all the Borough during the 2008/09 campaign. The government proposed 422 was attacked from all sides. Linked below are an EGRA/G Soc leaflet from September 2008 and a Declaration dated 14 October 2008 which was co-signed by Anne Milton and delivered by the signatories to GOSE (as was).


Nothing has changed locally since then, but there seems to be an acceptance that the 322 number cannot survive. The main change in terms of intention is that instead of locating the extra housing on one Green Belt site, a multitude of potential sites have been identified.

Option 4 would provide for the natural growth of the Borough and a flux of equal numbers of people in and out of the Borough. In addition to this most people would probably support provision of more affordable housing. Both could be accommodated within the 322 figure or thereabouts. The natural growth would provide some addition to the active labour supply.

The most obvious drivers for higher numbers are to meet the need to accommodate net international immigration and to meet the aspirations of business. It is a political decision as to whether the environment (Green Belt, character of the town) should be sacrificed to meet these needs.

 SUMMARY TABLE.  All figures are averages for 2011 to 2031.

In order of decreasing dwellings per year

Scenario A: dwellings per year B: dwellings per year Average of A &Bdwellings per year A:Population change per year A:Net migration per year B:Population change per year B:Net migration per year
10. All needs 1,066 1,066 1,066 2,725 1,660 2,436 1,428
1. Govt’s 2011 projection 704 704 704
11. Half affordable 644 644 644 1,585 739 1,365 560
3. Migration led 591 674 633 1,454 629 1,454 629
6. Jobs led (IER) 572 655 614 1,394 588 1,394 588
7. Jobs led (mid-range) 464 540 502 1,099 343 1,099 343
2. Govt’s 2010 projection 415 474 444 886 232 886 232
5. Jobs led (Exp.) 358 426 392 807 101 807 101
9. Dwellings led (SEP) 322 322 322 714 30 546  -109
8. Past completions 312 312 312 687 8 520 -130
4. Net nil migration 181 226 204 602 0 602 0

V1. 9.10.2013

As you can see this was an excellent summary by John Baylis for which I repeat my gratitude.  Feedback on John’s paper include:

From a former Planning Officer of a neighbouring authority:

Your paper is an impressive piece of work.

I would not disagree with your ‘Some Comments’ set out on pages 5 & 6 above the ‘Summary Table’.

My own comments are as follows;-

  1. It is impossible to assess the validity of the outcome figures of the various options since we do not know what assumptions are made in reaching their conclusions and even if we did it would be difficult to challenge those assumptions.
  2. You cannot simply seek to match jobs and housing numbers since social factors (such as people employed on short term contracts and both partners working) mean that these days people tend to ‘stay put’ in their existing house and simply travel (sometimes long distances) to their place of employment.
  3. In addition to the above, these days’ peoples’ work patterns are very different from 30 years ago. It is not unusual for people to work from home (allowing them to live some way from their ‘base’) and that pattern is likely to continue.
  4. Because of Guildford’s favoured geographical location (i.e. 30 miles from London, proximity to the A3/M25 giving easy access to Heathrow and Gatwick, access to attractive countryside, etc), Guildford will remain a favoured location and that will continue to be reflected in high property prices. This will inevitably result in people choosing to live distant from Guildford (where property is less costly) and travel into the town to work.
  5. Planning cannot control where people choose to buy houses or where people come from. Simply building more and more houses will inevitably result in more in-migration especially from London as property prices there continue to rise as a result of foreign investors
  6. And then there is the whole issue of the high price of property and the property market. At present so many young people cannot afford to buy houses and, as we know, developers only build if they can sell at a price which reflects development costs including land and profit. Ways of meeting local housing need is a key issue but this is an issue that is difficult for the Plan.

I know these comments do little to help reach a conclusion but I think they do demonstrate the impossibility of thinking there is a ‘right’ answer in terms of numbers. I would question whether the GBC paper ‘How Many New Homes?’ adequately takes account of the reality of the complex patterns of work/living of people in 2013.

Author: GuildfordPlan

GuildfordPlan is a 'whiteboard' set up by Julian Lyon to think out loud as part of the process of preparing the Guildford Society representations to the various Local Plan Consultations

5 thoughts on “Housing Numbers”

  1. I can’t help but agree housing need differing from 300 to 1000 for one year is no estimate, and way out of any statistical responce. which ever number we choose it can be right and can be challenged… as totally inaccurate an impossible task

  2. As I understand it, the Employment Study suggests that half of Guildford’s employed commute from outside the Borough [ some from quite a long way], and half of Guildford’s workers commute to employment outside the Borough. With this [ to me extraordinary] level of mobility, I find calculations as to employment demand for worker housing and worker demand for employment pretty meaningless in the restricted context of Guildford Borough.
    It’s the South-East Region that seems to be the study area and that, as they say, is a different ‘ball-game’.

  3. You are correct – as shown in the table I have linked to above. That data was taken from the 2001 census. The 2011 census data is due out in February 2014 and could show a greater inward commute. Two questions: 1) does a large inward commute suggest that all of those who commute would prefer (or should be able) to live in the Borough? 2) does it make sense to use 2001 data when 2011 data will be different – is this not a bit like playing Russian roulette with our Local Plan, our Borough and our children’s future?

  4. Reblogged this on My Normandy Village and commented:
    Very thorough analysis that gives insight into why there is a myriad of different potential targets. Although originally posted in October 2013 and therefore reflective of the 2009 SHMA that was available to the 2013 Guildford draft Local Plan, it raises serious questions that the new SHMA (dfecember 2013) has failed to address.

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