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The Insider's Guide to the Housing Delivery Test

Will the Housing Delivery Test (HDT) help your planning application or appeal?  How is it calculated and where can the underlying data be found? Here's your quick guide to:

• HDT results for every LPA, showing changes for every year over 2020-2023;
• NPPG on Five Year Housing Land Supply and the Housing Delivery Test;
• the standard method for calculating the number of homes required and where to find the original data;
• housing needs calculated using the standard method at 12th December 2024;
• a toolbox of ideas for making the case for housing development in planning applications and appeals.

The NPPF and the Housing Delivery Test

The National Planning Policy Framework published on 12 December 2024 sets out in paragraph 79 the consequences of failing the housing delivery test. It states that where delivery falls below 75% of the requirement, the “policies for the supply of land are out-of-date”. There has been a steady increase in the total number of local planning authorities affected by the housing delivery test penalties over time, and this is expected to intensify further in 2024 and beyond as a direct result of the December 2024 changes to the standard method for calculating housing needs.

Table 1: Number of LPAs failing the Housing Delivery Test over time

Impact of the Housing Delivery Test on planning decisions

The consequence of a HDT score of under 75% is to render relevant policies “out-of-date” which in turn triggers the “tilted balance” in applying the presumption in favour of sustainable development set out in NPPF 11(d), namely, “granting permission unless: (i) the application of policies in this Framework that protect areas or assets of particular importance provides a strong reason for refusing the development proposed; or (ii) any adverse impacts of doing so would significantly and demonstrably outweigh the benefits, when assessed against the policies in this Framework taken as a whole, having particular regard to key policies for directing development to sustainable locations, making effective use of land, securing well-designed places and providing affordable homes, individually or in combination.”

There are some important caveats which make the tilted balance less clear-cut than you might hope, explored in my blog back in January 2023 on whether it makes any difference to your planning appeal’s chances of success.  Despite the caveats, any local planning authority which over the past three years has delivered less than 75% of its housing requirement is undoubtedly on the back foot and should be more likely to welcome housing developments.

Understanding the Housing Delivery Test and using it to support your planning case

With effect from December 2024, the housing delivery test's measurement rule book sets out the simple calculation as follows:

Housing Delivery Test (%) =
    Total net homes delivered over 3 year period
    divided by
    Total number of homes required over 3 year period

The HDT results are published (in theory) in November or December each year but you can usually estimate them several months before publication using the methodology below.

“Optimism is evidence based” so using clear, objective facts in your planning statement or appeal statement of case can make all the difference to obtaining planning consent. If you know where to look, various official statistics provide valuable evidence you can use to support your planning case in a manner which will help a planning officer or planning inspector reach a positive decision. This is why understanding the housing delivery test and how you can use it to support a planning proposal can be so useful.

Using 'Net Homes Delivered' to support your planning application or appeal

'Net homes delivered' is the national statistic for net additional dwellings over a rolling 3 year period, with adjustments for communal accommodation. It's quite straightforward to obtain the 'net homes delivered' figure. Simply download these 2 tables from the DLUHC website here and add the totals for your local planning authority together:

• Table 122 for net additional dwellings over the previous 3 years; plus
• Table 124 for communal accommodation, converted into 'equivalent dwellings' for the previous 3 years. Communal accommodation is measured in bedspaces not dwellings, so there is a quick conversion to divide student bedspaces by 2.4 and other communal accommodation by 1.9 to give a proxy figure for the equivalent number of dwellings.

Using 'number of homes required' to support your planning application or appeal

Housing requirements are the LOWER of:
    • the adopted Local Plan housing requirement, providing this is less than 5 years old or has been reviewed and does not need updating; OR
    • the minimum annual local housing need figure, calculated using the “standard method”.

(Note areas covered by joint local plans, spatial development strategies or development corporations should check the HDT measurement rule book for full details.)

The standard method is set out in detail in the National Planning Practice Guidance on “housing and economic needs assessment” and is:
         - a baseline figure of 0.8% of the existing housing stock for the area using the latest available figure in MHCLG's table 125: dwelling stock estimates by LPA; 
         - adjusted by the most recent affordability ratio as published by ONS in its table 5c on median workplace-based affordability ratios.

If the affordability ratio exceeds 5, an upward adjustment is made to housing needs.  For each 1% the ratio is above 5, the housing stock baseline should be increased by 0.95%. an authority with an affordability ratio of 10 will have a 95% increase on its annual housing stock baseline. The formula used for this sliding scale of adjustment is:
Don't let the formula put you off - it is easier to use than it looks. Some useful examples of the calculation are found in the National Planning Practice Guidance here.

A calculation of each LPA's minimum annual local housing need using the prescribed 'standard method' as at December 2024 is available here, but it is always worth checking the original datasets linked above in case the Government have issued updated figures on dwelling stock (MHCLG's table 125) or updated the affordability ratio.

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