Strategic Housing Land Availability Assessment

A Strategic Housing Land Availability Assessment (SHLAA) is a technical exercise to determine the quantity and suitability of land potentially available for housing development. It is a required part of the evidence base needed for the preparation of a Local Plan (as specified in the National Planning Policy Framework, para. 159).

The Mayor carries out a London-wide SHLAA to inform the London Plan as it determines the borough housing targets that form a key part of the Plan.

How are sites assessed in the London SHLAA?

The London SHLAA includes an assessment of large sites (of 0.25 hectares and more in size) that is undertaken in partnership with boroughs and an assessment of capacity from small sites below this threshold. Large sites are identified from a range of sources, including:

  • Sites included in previous SHLAAs.
  • Sites allocated for development in development plans.
  • Sites with planning permission.
  • Sites identified by land owners and other interested parties through a 'call for sites' exercise.
  • Sites idenfified through development capacity studies undertaken by the GLA.

These sites are assessed by the local planning authority and the GLA through the SHLAA system in order to establish the capacity, availability, deliverability and their suitability for residential and mixed use development. This takes into account the range of planning policy, environmental and delivery constraints and the extent to which these can be mitigated or addressed during the plan period to 2041.

Potential housing delivery on smaller sites (under 0.25 hectares) is estimated in the SHLAA through a modelling exercise where average annual trends in housing completions are adjusted to take into account the expected impact of planning policy changes in the draft London Plan. This modelling takes into account public transport access levels (PTAL), proximity to town centres and rail/tube stations, the existing built form and heritage assets.

Progress update

The 2017 SHLAA has now been published and forms part of the evidence base for the draft New London Plan. The sites with planning permission (approvals) and allocated in development plans (allocations) listed in Annexes D and E of the SHLAA report are available to download from the London Datastore.

For further details please contact [email protected]


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