Britain's Big Ben has fallen silent for four years of renovation work, with its final 12 bongs ringing for midday in front of a crowd of over 1,000 people.

The repair work on the landmark looming over the Houses of Parliament in Westminster has sparked protests including from Prime Minister Theresa May.

MPs and parliamentary workers gathered to listen as the Great Bell chimed noon before being halted to allow work to begin.

Parliament bowed to pressure last week when it announced it would review the plans, which will silence the bell for the longest period in its 157-year history.

Mrs May said last week that it "can't be right" for Big Ben to be silent for four years.

But Downing Street indicated she would not mark the last chimes, saying only "she will be working in her constituency".

A spokeswoman said the question of whether the four-year period could be shortened was "a decision for the House of Commons Commission".

Steve Jaggs, keeper of the Great Clock, said there was "nothing fundamentally wrong" with the tower but work needed to be carried out now to protect it for future generations.

He said: "We are talking about a structure which stands 96 feet about the streets of London.

"It is an international symbol of democracy and we have to ensure that this tower can move forward for future generations to enjoy.

"There's nothing fundamentally wrong [compared to] same buildings of the same period of time but it is showing signs of disrepair now and unless we act soon it will take a lot longer to ensure it for future generations."

A brick enclosure in the tower will be replaced with glass to allow Big Ben to be viewed by people walking up the staircase.

The roof of the tower will be stripped off and restored, the bell frame repaired, leaks into the clock room stemmed and a lift installed.

Each clock face, which contains around 312 pieces of glass, will be re-glazed and crumbling stone work maintained.

The Ayrton Light, which shines out when the Commons and Lords are sitting, will be "off for some time" but the timescale will not be finalised until later this year.