EC4Y: 9 of 123 postcodes stand below a spring high tide

The ground at 9 of EC4Y's 123 postcodes (7%) 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 4.1 m and 13 m, measured from Ordnance Datum; the middle one stands at 8.7 m.
• 29 of 123 stand lower than the 1953 tide (5.41 m).
• 32 lie in the Environment Agency's Flood Zone 3 from the sea, mapped without defences.
• Mostly in City of London; partly in Westminster.