London, Dec 18 (IANS): The doors to Britain's most famous clock tower, London's Big Ben, was closed to the public in preparation for a facelift costing more than $40 million, reports said.

The iconic hourly gong of the bells fell silent for the first time since 2007 as the 157-year-old Elizabeth Tower that houses the clock and Westminster chiming bells closed doors on Saturday, Xinhua news reported.

The restoration project that could take around three years would see major work on the clock mechanism, including repairs to the clock's hands and its pendulum.

As part of the restoration, the famous bells would stay silent for a number of months, but no date for this part of the project was announced yet.

British Parliament officials at the Palace of Westminster have described the clock mechanism condition as "chronic".

Concerns were also raised about the fabric of the tower which was close to reaching an "acute" condition.

When the work on the tower is over, it would be easier for disabled people, to ascend to the top as the 334 steps would have the alternative new elevator.

The clock faces would be covered with sheets as the work progresses, though at least one clock face would remain visible at any time.

Although the Big Ben clock is one of the most photographed in the world, it is not the biggest.

By about a meter's difference in diameter, the clock faces on the Royal Liver Building in Liverpool is Britain's largest clock face.