Big Ben's famous quarter hour chimes fell silent this morning for the first time in 50 years.

While the 13.8 ton hour bell, after which Big Ben is actually named, will continue to chime, the quarter chimes will remain silent for a month.

A bearing in the arm that holds one of the hammers will be replaced.p>

The four not tune, which was originally written in 1793, is taken from Handel's Messiah.

It's based on the words "All through this hour, Lord, be my guide/ That by Thy Power/ No foot shall slide."

Big Ben first chimed out of Westminster on May 31, 1859.

Installed in St Stephen's Tower, the Great Clock at the northern end of the Palace of Westminster has been operating since May 31 1859.

This is the first major repair work on the bells since 1955.

The repair work will be done at the Whitechapel Bell Foundry in East London.