Laser surgery for Lord Mayor's coach

The Lord Mayor's State Coach, a priceless piece of London's history, is close to falling apart, experts admitted today.

They say the vibration caused by driving the coach, which was built in 1757, has caused large cracks to appear throughout its body. The coach is so complex that building a replica would cost about ?2 million.

"It just wasn't designed for London's modern roads," said Duncan Lees, a restoration expert at Plowman Craven Associates who is working on the coach.

"God forbid it would happen, but there is a chance that pieces could just fall off during the Lord Mayor's parade - and the structure has a lot of cracks throughout."

The Lord Mayor's coach is one of only two state coaches in use in England, the other being the Queen's Gold Coach. But the Lord Mayor's is far more lavish, built at a time when the monarch had to ask the mayor's permission before entering the capital.

The carriage is stored at the Museum of London and is owned by the Corporation of London.

In an attempt to save it, experts today began scanning the entire structure with lasers to build a three-dimensional

computer model to monitor the coach's health, and to create replacement parts as they fail.

Over the next three weeks, the coach will be bombarded by lasers to measure every part of the doors and golden cherubs to an accuracy less than the width of a human hair.

"It's like building up a massive jigsaw puzzle, and we'll be taking 2,000 pictures every second, so it will be a very detailed model," said Mr Lees.

Visitors to the Museum of London will be able to watch the researchers at work, and a giant plasma screen above the carriage will show the current state of the model.