Westminster Section 257 Converted Flats: Do They Need a Licence?

Section 257 of the Housing Act 2004 creates a particular category of HMO: a building converted into self-contained flats where the conversion did not meet the appropriate building standards and still does not meet them, and less than two-thirds of the flats are owner-occupied. Westminster has explicitly excluded these buildings from its local licensing schemes — but that exclusion is narrower than most landlords assume.

What Section 257 Means

A Section 257 HMO is not a traditional shared house. It is a converted building — typically a Victorian or Edwardian terraced house split into separate flats — where the conversion did not comply with the appropriate building standards and still does not comply with them. If fewer than two-thirds of the flats in the building are occupied by their owners, the entire building meets the statutory definition of an HMO under Section 257.

This matters because the building as a whole has HMO status, even though each flat inside it is self-contained with its own kitchen, bathroom and entrance.

The Block-Level Exclusion

Westminster City Council has explicitly excluded Section 257 converted blocks from both its additional HMO licensing scheme and its selective licensing scheme. The building itself does not need a block-level licence.

This exclusion means the freeholder or superior leaseholder does not have to obtain a single licence covering the entire converted building. For purpose-built blocks with a resident freeholder managing a handful of flats, this is a genuine exemption from additional local compliance costs.

The Trap: Individual Flats Still Need Licences

Here is where landlords get caught. The block-level exclusion does not extend to the individual flats inside the building. Each privately rented flat within a Section 257 block is assessed independently based on its own occupancy:

A flat let to a single household or two sharers in one of the 15 designated wards requires its own selective licence. The fact that the building is a Section 257 HMO does not exempt the individual unit from selective licensing.

A flat let to three or four tenants forming two or more households requires an additional HMO licence — borough-wide, all 18 wards. This applies even though the converted block itself is excluded from additional licensing.

A flat let to five or more occupants from two or more households requires a mandatory HMO licence. No exemption applies.

The common mistake is assuming that because the building is excluded, the flats inside it are also excluded. They are not. The exclusion operates at the building level only. Each let flat is a separate licensable unit.

Practical Implications for Freeholders

If you own a converted building with six flats, four of which are rented out:

• The building does not need a block-level licence under Westminster's local schemes
• Each of the four rented flats needs its own individual licence based on its occupancy and ward location
• You cannot rely on a single block-level application to cover all the flats — each one goes through the portal separately
• For eligible Selective Licensing applications, the multi-dwelling block discount reduces Part A by £125 on the second and subsequent concurrent applications

How to Check Whether Your Building Qualifies as Section 257

Three conditions must all be met:

1. The building has been converted into self-contained flats
2. The conversion did not comply with the appropriate building standards and still does not comply with them
3. Less than two-thirds of the flats are owner-occupied

The age of the conversion or the absence of a completion certificate alone does not determine Section 257 status. The test is whether the conversion failed to meet the appropriate building standards and still fails to meet them, alongside the owner-occupation threshold above.

If you are unsure, the council's private sector housing team at [email protected] can advise on a specific building's Section 257 status.

The Westminster Landlord Licensing Guide includes a Section 257 diagnostic checklist and the full decision flowchart for determining which licence each individual flat needs.

See more England guides →