It is one of London’s most famous landmarks – but the future of Big Ben could be at risk, because it’s starting to lean to one side.
Surveyors say St Stephen’s clock tower, which houses the bell known as Big Ben, is sinking into the banks of the river Thames. At the moment, the top of the 315 foot high tower is listing 0.26 degrees to the northwest, putting it around 18 inches out of alignment.
The state of the structure only emerged after London Underground commissioned an engineers’ report into the Jubilee line extension, which goes through Westminster tube station.
It shows the rate of movement has sped up over the last few years – although experts are at a loss to explain why. It is thought the tilt could have been exacerbated by decades of building works underground – or its clay foundations could be drying out.
You can see it if you stand on Parliament Square and look east. Professor John Burland
John Burland, emeritus professor at Imperial College London, who has worked on the tower, said the tilt was visible to the naked eye: “You can see it if you stand on Parliament Square and look east towards the river”, he said. “If it started greater acceleration, we would have to look at doing something, but I dont think we need to do anything for a few years yet.”
It has already caused some cracks to develop in some corridor and office walls in the House of Commons. Although there’s no danger of it crashing over just yet – at the current rate, it would take around 4,000 years before it reaches the same angle as the Leaning Tower of Pisa, and even longer to come anywhere close to collapse.