The housing delivery test aims to measure how effectively each local authority is delivering housing. It works by comparing each councils' level of housing delivery - using the the net additional dwelling figures - over a three-year period to the total number of homes required.
The test results for the 2016-19 period were published by the Ministry of Housing, Communities and Local Government (MHCLG) last week, having been postponed for three months following the December general election. They are the second annual test results that the MHCLG has published.
Under the National Planning Policy Framework (NPPF), all councils have to demonstrate a five per cent land supply buffer as standard, in addition to their required five-year supply of deliverable housing sites.
But under the test, authorities delivering under 85 per cent of their housing requirement will have to provide a "buffer" of sites for 20 per cent more homes than are needed to meet their five-year target.
The penalties take effect from the moment the results are published, according to the 2019 National Planning Policy Framework (NPPF).
The test results show that 109 authorities - exactly 33 per cent - scored under 95 per cent and face a penalty under the test, which means that at minimum they will have to produce an action plan showing how they will improve their housing delivery performance over the next year.
Of these, 83 authorities fall under the 85 per cent threshold will have to find the additional 20 per cent buffer with eight of these facing the most severe penalty, the NPPF's presumption in favour of sustainable development.
Of the 83 that will be required to show the 20 per cent buffer, 63 already have a 20 per cent buffer following the 2018 test results.
However, 24 authorities that scored under 85 per cent last year and had to provide a 20 per cent buffer scored above this threshold this year. This means they can now add the standard five per cent buffer to their land supply target rather than the higher 20 per cent (see below).
Planning research in December estimating the 2019 results predicted that 20 councils would be able to reduce their land supply buffer in this way under the test. One authority on our list was not included in the actual list above, with five further authorities in the latter group but not in our estimated version.
Full details of all the 109 councils that are being sanctioned under the test, including their housing requirement and delivery figures can be found here.