Planning policy monitoring


Assessment of housing land supply

Assessment of housing land supply (2022-27)


Purpose of report

1.1 The National Planning Policy Framework (NPPF) says strategic policies should include a trajectory illustrating the expected rate of housing delivery over the plan period, and all plans should consider whether it is appropriate to set out the anticipated rate of development for specific sites.

1.2 Local planning authorities should identify and update annually a supply of specific deliverable sites sufficient to provide a minimum of five years’ worth of housing against their housing requirement set out in adopted strategic policies or against their local housing need where strategic policies are more than five years old.

1.3 In the absence of a 5-year supply, development plan policies may be treated as out-of-date, making the area susceptible to speculative development pressures.

1.4 Local planning authorities should also identify a supply of specific developable sites or broad locations for growth for years 6 -10 and where possible, for years 11-15.

1.5 This report outlines the deliverable and developable housing land supply for North Northamptonshire in relation to current housing requirements.

1.6 This report relates to the monitoring year 2021/22, the first full monitoring year since the creation of the new North Northamptonshire Council (NNC) on 1st April 2021. However, this is the second report to assess housing land supply on a North Northamptonshire-wide basis as a whole (rather than on former local planning authority areas) and also against Local Housing Need (LHN) rather than housing requirements set out in the JCS (this is explained further below).

1.7 The approach to reporting housing land supply on a North Northamptonshire-wide basis rather than sticking with the former local planning authority areas (as some other new unitary councils in the UK do) was agreed at the North Northamptonshire Planning Policy Executive Advisory Panel in June 2021.

1.8 The information set out below on housing land supply will also be included in the full North Northamptonshire 2021/22 AMR, which is to be published soon after this specific report.

Housing target

1.9 The North Northamptonshire Joint Core Strategy (JCS) was adopted in July 2016 and remains extant as Part 1 of the Local Plan for NNC while a new plan – the North Northamptonshire Strategic Plan – is developed. The JCS outlines the level of housing to be planned for over the period 2011-31 and sets this out by the former local authority areas as well as North Northamptonshire as a whole. In accordance with JCS Policy 28, this is as outlined in Table 1 below.

1.10 As of July 2021 however, the JCS turned 5 years old and as per national policy (para 74 of the NPPF) this means that the housing requirements within should be superseded by Local Housing Need (LHN). In North Northamptonshire LHN for the 2021/22 year is similar to the JCS housing requirements in all the former local planning authority areas. These are also set out in Table 1 below. LHN can change annually depending on any changes made by government, the figures that will be used for the 2022/23 year have already been released, North Northamptonshire will use a LHN figure of 1,874 for that particular monitoring year.

Table 1 – Housing requirements for North Northamptonshire and former LPAs

Area (former LPA)

JCS Policy 28 annual housing requirement

Local Housing Need (LHN) using Standard Method




East Northamptonshire









North Northamptonshire



Identifying the supply of deliverable and developable sites

1.7 Existing planning consents do not represent the only source of housing land supply when identifying deliverable or developable sites. As referred to above, the local authority is required to identify five years’ worth of deliverable sites and 6 -15 years’ worth of developable sites.

1.8 The NPPF defines what is meant by deliverable:

“To be considered deliverable, sites for housing should be available now, offer a suitable location for development now, and be achievable with a realistic prospect that housing will be delivered on the site within five years. In particular:

a) sites which do not involve major development and have planning permission, and all sites with detailed planning permission, should be considered deliverable until permission expires, unless there is clear evidence that homes will not be delivered within five years (for example because they are no longer viable, there is no longer a demand for the type of units or sites have long term phasing plans).

b) where a site has outline planning permission for major development, has been allocated in a development plan, has a grant of permission in principle, or is identified on a brownfield register, it should only be considered deliverable where there is clear evidence that housing completions will begin on site within five years.”

1.9 The latest National Planning Practice Guidance (NPPG) (Paragraph: 030 Reference ID: 3-030-20180913) further advises that:

“In order to demonstrate 5 years’ worth of deliverable housing sites, robust, up to date evidence needs to be available to support the preparation of strategic policies and planning decisions. Annex 2 of the National Planning Policy Framework defines a deliverable site. As well as sites which are considered to be deliverable in principle, this definition also sets out the sites which would require further evidence to be considered deliverable, namely those which:

  • have outline planning permission for major development;
  • are allocated in a development plan;
  • have a grant of permission in principle; or
  • are identified on a brownfield register.

Such evidence, to demonstrate deliverability, may include:

  • current planning status – for example, on larger scale sites with outline or hybrid permission how much progress has been made towards approving reserved matters, or whether these link to a planning performance agreement that sets out the timescale for approval of reserved matters applications and discharge of conditions;
  • firm progress being made towards the submission of an application – for example, a written agreement between the local planning authority and the site developer(s) which confirms the developers’ delivery intentions and anticipated start and build-out rates;
  • firm progress with site assessment work
  • clear relevant information about site viability, ownership constraints or infrastructure provision, such as successful participation in bids for large-scale infrastructure funding or other similar projects.”

1.10 The NPPF also defines what is meant by developable:

“To be considered developable, sites should be in a suitable location for housing development with a reasonable prospect that they will be available and could be viably developed at the point envisaged.”

Windfall allowance

1.11 The NPPF simply defines windfall sites as not specifically identified in the development plan. They normally comprise previously developed sites that become unexpectedly available. Local planning authorities can make a windfall allowance in the five-year supply if they have compelling evidence that such sites have consistently become available and will continue to provide a reliable source of supply.

1.12 As past reviews of housing land supply have demonstrated, windfall development has contributed to the provision of new housing across North Northamptonshire and on this basis provision is made for the continuing contribution of this in the assessment of North Northamptonshire’s housing land supply. However, mindful to avoid double counting of smaller sites with an extant planning permission, this element of supply is only included from year 3 onwards in the 5-year assessment period (2022-27).

Five year supply of deliverable sites

Appropriate buffer

2.1 When identifying a five-year supply, the NPPF requires the addition of a 5% buffer to the housing requirement to ensure choice and competition in the market land. This rises to 10% where the local planning authority wishes to demonstrate a five-year supply of deliverable sites through an annual position statement or recently adopted plan, to account for any fluctuations in the market during that year. This subsequently rises to a 20% buffer where there has been significant under delivery of housing over the previous three years, in order to improve the prospect of achieving the planned supply. The NPPF says that from November 2018 significant under delivery will be measured against the Housing Delivery Test (HDT) and will be defined as delivery below 85% of the housing requirement. None of the four former councils in North Northamptonshire were found to be significantly under delivering in the latest Housing Delivery Test calculations released by the government in January 2022, as can be viewed in Table 2 below, and therefore a 5% buffer is applied for North Northamptonshire. It is anticipated that government will release these calculations on a North Northamptonshire-wide basis from next year onwards.

Table 2 – Latest housing delivery test results per area of North Northamptonshire

Area (former LPA)

HDT Score



East Northamptonshire






Treatment of past under-provision

2.2 There are two basic methods of dealing with past shortfall. It can be met over the five-year period (the “Sedgefield” approach) or over the remaining plan period up to 2031 (the “Liverpool” approach). The NPPF does not explicitly state which method is preferable when addressing shortfall although Planning Practice Guidance states that ‘The level of deficit or shortfall will need to be calculated from the base date of the adopted plan and should be added to the plan requirements for the next 5-year period (the Sedgefield approach)’. (Paragraph: 31 Reference ID: 68-031-20190722). The former local planning authorities of North Northamptonshire have historically used the Sedgefield approach when it comes to these calculations.

2.3 However, given the JCS is now more than five years old, the JCS housing requirements are now superseded by LHN and therefore shortfall against the past JCS requirements is no longer taken into account as the standard method for calculating LHN factors this in (past shortfall against the JCS requirement is denoted at Appendix 1 for reference). This is as per NPPG guidance (Paragraph: 031 Reference ID: 68-031-20190722) which states:

“Step 2 of the standard method factors in past under-delivery as part of the affordability ratio, so there is no requirement to specifically address under-delivery separately when establishing the minimum annual local housing need figure.”

Five year period

2.4 The Planning Practice Guidance was updated in early 2019 to state that “Sites should be deliverable in years 1 to 5 of the plan period, and subsequently reviewed and their status updated each year in the Authority Monitoring Report and Annual Position Statement (if confirming the 5 year housing land supply)” therefore as of the 2018/19 monitoring year, the former sovereign councils in North Northamptonshire prepared their Housing Land Supply positions by treating the current year as ‘year 1’. However since this, the guidance was updated again in July 2019 where this text was removed, potentially leaving the 5 year assessment period open to interpretation (past joint AMRs have used the approach to not include the current year), albeit text at Paragraph 022 was introduced that states; “To ensure that there is a realistic prospect of achieving the planned level of housing supply, the local planning authority should always add an appropriate buffer, applied to the requirement in the first 5 years (including any shortfall)”. The usage of the word ‘first’ indicating that the assessment should start from ‘year 1’ (i.e, for this AMR the 2022/23 to 2026/27 years are assessed). For clarity, the NPPF does not specify which 5-year period should be calculated and para 73 simply refers to ‘five years’ worth’ of housing.

North Northamptonshire Council: Assessment of housing land supply, 2022-23

Deliverable sites

3.1 Table 3 below details the composition of deliverable housing sites identified in North Northamptonshire over the five-year assessment period, broken down by area. This information was derived from the housing site schedules produced for each area:

The methodology for calculating deliverable housing supply across the different areas varies to reflect local circumstances, however a standardised approach for North Northamptonshire will be introduced at the earliest opportunity. As can be seen, the area has an identified housing supply of 13,979 dwellings over the assessment period.

Table 3 – Composition of identified housing supply, 2022-27


Yield 2022-27





East Northamptonshire




Total identified supply 2022-27


Five year supply assessment

3.2 Table 4 below outlines the assessment of North Northamptonshire’s housing land supply 2022-27 against LHN. As can be seen North Northamptonshire has 7.46 years housing land supply.

Table 4 – Requirements for North Northamptonshire for the 5-year period 2022-2027 measured against LHN


LHN Housing Requirement 2022-27 (1,784 x 5)



LHN Housing Requirement + 5% buffer



Identified Housing Supply 2022-27



Number of years deliverable housing land supply 2022-27 (C/B x 5)


Appendix 1 – Past shortfall in North Northamptonshire

Table 5 below outlines that over the period 2011-22 17,808 dwellings were built in North Northamptonshire. Compared to the requirements of JCS Table 5 over the same period (1,750 x 11 years = 19,250 dwellings), this represents a shortfall of 1,442 dwellings, however this is no longer considered in the housing land supply calculations when using LHN.

Table 5 – Housing delivery in North Northamptonshire relative to JCS Policy 28, 2011-22

Recorded completion 2011/12


Recorded completion 2012/13


Recorded completion 2013/14


Recorded completion 2014/15


Recorded completion 2015/16


Recorded completion 2016/17


Recorded completion 2017/18


Recorded completion 2018/19


Recorded completion 2019/20


Recorded completion 2020/21


Recorded completion 2021/22


Total Completions 2011-22


JCS Requirement 2011-22 (1,750 x 11)


Difference 2011-22


Last updated 20 April 2023