SW1W: 7 of 341 postcodes stand below a spring high tide

The ground at 7 of SW1W's 341 postcodes (2%) is lower than an ordinary spring high tide at London Bridge (3.9 m above Ordnance Datum).

• Ground at eight in ten of its postcodes: between 4.4 m and 6.7 m, measured from Ordnance Datum; the middle one stands at 5.7 m.
• 139 of 341 stand lower than the 1953 tide (5.41 m).
• 113 lie in the Environment Agency's Flood Zone 3 from the sea, mapped without defences.
• Mostly in Westminster; partly in Kensington and Chelsea.