The Thames Barrier, originally designed to last until 2030, was opened 40 years ago this week.

It is one of the largest movable barriers in the world and is operated and maintained by the Environment Agency. The Barrier and the other flood defences across the wider estuary protect 125 square kilometres of central London, encompassing 1.42 million people, four World Heritage sites, more than 4,000 listed buildings, 711 healthcare sites, 116 railway and tube stations and more than 300km of major roads. The value of residential property protected stands at £321 billion.

Without the barrier, storm surges and frequent tidal flooding of the Thames would submerge buildings along the river as well as the underground, wrecking properties and livelihoods and causing billions of pounds worth of devastating damage.

In its 40 years, the barrier has closed 221 times for flood defence purposes, underlining its importance to helping London thrive.

The original design life was only to 2030, but due to the excellent design and build, the Thames Barrier will continue to protect London until 2070.

The Thames Barrier’s future is encapsulated in the Thames Estuary 2100 plan, updated last year. This sets out how flood risk will be managed in the Thames estuary to the end of the century and beyond from both the existing risks faced from tidal flooding, as well as the growing risks that climate change will bring.

To ensure the capital is protected over the longer term, the Environment Agency is committed to working with partners to review and decide on an end-of-century option by 2040.