SE1: 1,418 of 1,996 postcodes stand below a spring high tide

The ground at 1,418 of SE1's 1,996 postcodes (71%) 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 2.2 m and 4.5 m, measured from Ordnance Datum; the middle one stands at 3.4 m.
• 1,967 of 1,996 stand lower than the 1953 tide (5.41 m).
• 1,871 lie in the Environment Agency's Flood Zone 3 from the sea, mapped without defences.
• Mostly in Southwark; partly in Lambeth.