Thatcher government contemplated blowing up Thames defences

Margaret Thatcher’s government contemplated blowing up Thames defences in Essex and Kent to save central London from severe flooding, secret documents show

It was one option put forward by ministers when a dock strike in 1982 held up parts needed for the completion of the Thames barrier.

The situation compounded existing fears of a serious flood with “disastrous consequences” as the banks of the river had been raised in preparation for the barrier. It meant that any tidal surge before completion would be funnelled upstream.

The government however recognised the “major political difficulty” in “deliberately flooding Kent and Essex in order to protect central London”.

A Cabinet Office memo referred to a paper by the Minister of Agriculture which considered a number of options, including trying to secure a resolution of the pay dispute between the Tees and Hartlepool Port Authority and the dockers, trying to persuade the dockers to release the gates and using the military to load the gates.

The memo also revealed the paper had suggested “if all else fails it might be necessary to provide that, if a major surge of water was threatened, that flood defences downstream would be breached so that some of the water would flood low-lying land in Essex and Kent rather than central London”.

It acknowledged however that “this approach seems unlikely to be practicable”.

“It would involve the destruction of large sections of defences which together have cost £20 million,” the memo stated.

“Explosive charges would have to be laid in advance so that they could be detonated when it seemed that a tidal surge sufficient to flood London seriously was on its way.”

Adding “There is a major political difficulty in that the Government would have to take responsibility for deliberately flooding Kent and Essex in order to protect central London”.