SW1A postcode district: City of Westminster and around

SW1A is a postcode district in England, with 145 postcodes in use in 3 sectors. It has postcodes in City of Westminster and Wandsworth. It is split between 2 councils: Westminster (143 postcodes) and Wandsworth (2).

Postcodes in use: 145
Sectors: 3
Councils: 2 councils
Places: 2 places

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026. See all our data sources

Every postcode in SW1A, and which are new since 2020

New since 2020: 5
In use before 2020: 140

Of the 145 postcodes in SW1A that ONS places, 5 are new since 2020 and 140 were in use before 2020.

Each mark is a postcode's centre point as ONS gives it, not a building. Press one to see its postcode and open its page. New since 2020 means it came into use in January 2020 or later. No boundary is drawn. Where marks overlap, the one first in the key is drawn; the counts include every postcode. Names in italics are council wards: we hold no town or village names here.

The middle of its postcodes: latitude 51.5046, longitude -0.1322. Open this area on OpenStreetMap

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026, the centre point of each postcode; when each came into use: the same directory; roads, rivers and built-up areas: Contains OS data © Crown copyright and database right 2026. Drawn by us. Street map: Ordnance Survey, OS Open Zoomstack, Open Government Licence v3.0, drawn with MapLibre. How we use them

The 5 newest postcodes

SW1A 1NFJune 2026 SW1A 2DADecember 2025 SW1A 1AHDecember 2023 SW1A 2BHJune 2023 SW1A 2BTJuly 2022

What broadband can you get in SW1A?

Ofcom reports on 125 of the 145 postcodes in SW1A. At 76 of them every home and business can get gigabit broadband.

Postcodes where every home can get gigabit76 of 125

Postcodes where every home can get superfast76 of 125

Ofcom gives each postcode's share of homes and businesses, not how many there are, so these count postcodes. Each postcode page has its own figures. A provider's checker answers for one address.

Check one address on Ofcom's checker

Source: Ofcom, Connected Nations, Spring 2026, data for January 2026, Open Government Licence v3.0. How we use it

Is SW1A at risk of flooding?

48 of the 145 postcodes in SW1A have a home or business in an area at risk of flooding from rivers or the sea, the Environment Agency says. At those, it puts 6 homes and businesses in an area at high or medium risk.

Homes and businesses in an area at risk, at 48 of 145 postcodes High: 6Very low: 207

High: 3.3% or more a year (1 in 30). Medium: 1% to 3.3% a year. Low: 0.1% to 1% a year. Very low: under 0.1% a year (1 in 1,000). Each band is the chance of flooding in any one year.

Homes and businesses in an area at risk of flooding from rivers or the sea, as the Environment Agency counts them, added up over the postcodes. It is for the land, not each building, and leaves out surface water, groundwater and sewers. Each postcode page has its own figures and its flood warning areas.

Source: Environment Agency, Risk of Flooding from Rivers and Sea (postcodes in areas at risk), published 6 July 2026, Open Government Licence v3.0. How we use it

What do homes sell for in SW1A?

HM Land Registry records one sale of homes in SW1A in the 12 months to August 2026: too few to give a typical price.

Flat or maisonette 1 sale, too few to price

Standard sales of homes at market value. A typical price is the median, the middle sale. Sales take weeks to be registered, so the last month or two are incomplete. Each postcode page gives the figure for its own postcode sector.

Source: HM Land Registry Price Paid Data, files dated 28 September 2026. Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0. How we use it