London: A lamp at the top of the Elizabeth Tower which houses the UK’s iconic Big Ben will be switched off for the first time in more than 70 years, authorities said on Saturday.

Located above the Great Bell known as Big Ben, the Ayrton Light — which is switched on in the evening whenever Parliament is sitting — needs to be fully dismantled and restored. A temporary light will replace it, the House of Commons has said.

Installed in 1885, the historic lamp was previously turned off only during both world wars. Big Ben will not chime regularly until 2021 because of repairs to the tower, the BBC reported.

The light is said to have been installed at the request of Queen Victoria, so that she could see from Buckingham Palace when members of either the Commons or the Lords were sitting after dark.

The lamp is named after Acton Smee Ayrton, a Liberal politician who was First Commissioner of Works between 1869 and 1873.

It is not yet known when the light will switch off, or how long it will be off for.

Big Ben will go silent from midday on Monday. The House of Commons has said it will look again at the length of time it will be silenced after “concerns”.

Parliament said it had to protect workers carrying out the renovations.

But Prime Minister Theresa May said “it can’t be right” that the bell will not chime regularly again for four years.

It will still sound for important events including New Year’s Eve and Remembrance Sunday. PTI MRJ EMY