Bong! Big Ben's chimes ring out again

London is once again hearing the regular "bongs" of Big Ben after seven weeks of silence.

The famous chimes rang out across Westminster at noon following almost two months of maintenance work.

An electric back-up system has kept the Great Clock ticking since August 11 but Big Ben and the quarter bells have remained quiet to allow experts to carry out necessary repairs.

The work has included the replacement of the bearings on the strike train, which operates the hour bell and the going train, which controls the clock itself.

A re-synchronisation of all the bells, including Big Ben, took place, on Saturday night and the clock hands and weights were also reconnected during the weekend, which will allow it to be fully restarted.

Engineers will monitor the restored clock mechanism closely to ensure it is keeping the right time.

Michael McCann, Keeper of the Great Clock, said: "We resynchronised the bells at the weekend. The first strike of the bell has to be accurate to within a second. It took us about three hours to do it all on Saturday."

The programme of planned works has been carried out prior to the famous clock's 150th anniversary in 2009.

Big Ben is the nickname for what is officially called the Great Clock, but strictly speaking Big Ben refers only to the 13.5-tonne bell that chimes the hours.

It was named after Sir Benjamin Hall, who was Commissioner of Works when the bell was installed in 1859.

In the past the clock has been stopped accidentally on a number of occasions - by weather, workmen, breakages and birds.

© Independent Television News Limited 2007. All rights reserved.