Father Thames is a crotchety and unreliable old man. No one in their right mind would build a capital city on his floodplain.

Forget, for a moment, the recent freak weather. Just extend your little finger across the breakfast table and contemplate its height. High water at London Bridge increases by that much every year. Piffling, you will say, but it adds up to two feet a century.

You can blame Scotland, as you often do. Relieved of its weighty burden of the last Ice Age, the northern kingdom is still rising, and as a consequence the whole island is on the tilt; southern England from the Wash to the Severn is sinking.

At the same time London is settling into its own plastic foundation of clay, and the decline of industry, which used to extract vast amounts of groundwater, means that the water table is rising. London Underground pumps the equivalent of 3,000 swimming pools out of its tunnels a day.

Surge tides from the North Sea are London’s traditional enemy, which is why in 1982 the Thames Barrier was opened at Woolwich. This brilliant and unimaginably expensive engineering feat protects London for now, but in not much more than 20 years it will have to be made higher.

An unfettered Thames had been bursting its banks for centuries. In medieval times it regularly overflowed from the City to Westminster, creating a vast and fetid lake fed additionally by its stinking tributary, the Fleet.

There was a mighty inundation in 1236, recorded by John Stow in his Chronicles of England.

“The River Thames, overflowing its banks, caused the marshes all about Woolwich to be all a sea wherein boats and other vessels were carried by the stream, so that besides cattle a great number of inhabitants there were drowned, and in the great Palace of Westminster men did row with wherries in the midst of the Hall.”

It happened again in 1663, as recorded by Samuel Pepys in December 7. “There was last night the greatest tide that ever was remembered in England to have been in this river, all Whitehall having been drowned.”

Constrained by the building of the Victoria Embankment in the 19th century, the river behaved itself a little better, until on January 6, 1928, the tide in central London rose to 1.8m (6ft) above the predicted level.

Flood reports started coming in from Battersea, Poplar and Greenwich. The embankment at Temple station was awash, as was the whole of Old Palace Yard, Westminster.

The embankments could not contain the water. The first section to give way was at Millbank; the Tate Gallery was flooded almost to the tops of its ground-floor doors, and its collection of Turners was damaged. Lots Road power station near Chelsea, Wandsworth gasworks and the Blackwall Tunnel were all partly flooded.

But the worst consequence was the failure of a 25m stretch near Lambeth Bridge, drowning 14 people and leaving another 4,000 homeless.

Central London escaped the worst effects of the great flood of 1953, but the barriers subsequently erected around East Anglia merely moved the problem, forcing even more water up the Thames and making construction of the Barrier ever more urgent.

London had another wake-up call as recently as September 2000, when a tributary of the Thames, the Roding, overflowed its defences and flooded 320 properties in the Wanstead and Woodford areas of East London.

One way to protect London would be to raise the riverside defences until they are as high as the lampposts. The idea has been consistently rejected on the ground that Londoners would not be able to see the river that both threatens and enchants them.