As the Thames Barrier reaches its fortieth anniversary, officials have said it will need upgrades in the future to cope with rising sea levels and extreme weather caused by climate change.

The structure – which has been operational since 1982 but was officially opened on 8 May 1984 – helps to protect areas of London lying in the floodplain from high tides and storm surges moving up from the North Sea. Discussions into building some form of enhanced flood protection along the Thames were spurred by the North Sea flood of 1953, which killed over 2,500 people across four countries.

In its 40-year history, the barrier has closed 221 times for flood defence purposes, but a plan dubbed Thames Estuary 2100 is currently fielding options to extend its lifespan to the end of the century.

At the time of its construction, the barrier was expected to be used 2-3 times per year, but by the mid-2000s it was being operated 6-7 times a year. In the 2010s, the barrier was generally closed twice a year, but...