London's Big Ben is leaning!

In fact, they claim to have found that the world's largest four-faced chiming clock at the British Parliament has developed a tilt which is getting worse every year, leading newspaper 'The Sunday Telegraph' reported.

The top of the tower is now almost one-and-a-half feet off the perpendicular -- and the experts say that if the movement continues uncorrected, Big Ben would one day topple.

But, breathe easy. At its current speed, it would take some 4,000 years to reach the angle of the Leaning Tower of Pisa, and even longer to hit tipping-point, say the engineers.

They believe that the tower is gradually "sinking" or settling into the land on which it is built. But the pattern is uneven, with the sinking occurring more quickly on the north side than the south.

The problem has been blamed on decades of building work that have gone on around the foot of the structure -- 315 ft tall, with 11 storeys and 393 stairs -- since it was completed in 1858.

The tower is now leaning towards the northwest at an angle of 0.26 degrees, meaning the top of the tower is 1ft 5in from vertical.

John Burland, emeritus professor and senior research investigator from Imperial College London who has worked on the Big Ben tower, said: "The tilt is now just about visible. You can see it if you stand on Parliament Square and look east, towards the river."

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