LONDON – Big Ben has a little bend.

Experts say the neogothic clock tower — one of the world’s most recognizable landmarks — is gently leaning to one side. Documents recently published by Britain’s Parliament state that the top of Big Ben’s gilded spire is nearly 18 inches out of line.

The 315-foot tower is leaning to the northwest at an angle of 0.26 degrees, according to a report from 2009 that was recently obtained by the Sunday Telegraph through a Freedom of Information Act request.

But there’s no cause for alarm, experts said. It would take thousands of years before the London landmark’s tilt matches that of the Leaning Tower of Pisa.

The clock tower — colloquially known as Big Ben for its massive bell — has been slightly off-center since it was erected in the mid-19th century. Like many old buildings, its position has been shifting imperceptibly for years due to environmental factors such as seasonal temperature and moisture level changes.

“We’re talking about unbelievably small movements,” said John Burland, an engineering professor at Imperial College London who has been involved in the study of the tower.

“At the present rate, it will be 10,000 years before we reach that,” he added, referring to comparisons with the tower in Pisa, Italy.

Even so, the tilt might now be just about visible.

“Anyone who stands there and looks may say, ‘I don’t think it’s vertical,’ and they are quite right,” he said.

The level of movement has been less than 1 millimeter a year since experts began measuring it in the 1970s, Burland said. Most of the tilt occurred when the tower was being built in the 1840s and 1850s.