SE17: 678 of 684 postcodes stand below a spring high tide

The ground at 678 of SE17's 684 postcodes (99%) 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 2.5 m and 3.5 m, measured from Ordnance Datum; the middle one stands at 3.0 m.
• All 684 stand lower than the 1953 tide (5.41 m).
• 593 lie in the Environment Agency's Flood Zone 3 from the sea, mapped without defences.
• In Southwark.