The carriage was withdrawn from service in 1905 when the Metropolitan Railway was electrified.

BBC: Revamp for 'oldest' Tube carriage

Next January it will be 150 years since the first ever London Underground railway operated on the Metropolitan Railway between Paddington and Farringdon.

BBC: London Underground celebrations to mark 150 years

The guests were shown the plush red velvet interior of the 1892 carriage, Metropolitan Railway Jubilee Carriage No 353, which is the oldest operational Tube carriage.

BBC: Queen and Catherine visit Baker Street Tube station

The pair had different visions, with Watkin, who wanted to build a Channel tunnel rail link to France, seeing the Metropolitan as a mainline railway, while Forbes preferred shorter extensions.

BBC: Tube 150th anniversary: Exploiting the 'suburban dream'

The restoration work will take about a year to complete and will incorporate early Metropolitan Railway design and construction.

BBC: Revamp for 'oldest' Tube carriage

Metropolitan Railway Carriage Number 353 was built in 1892 and ran on what is now known as the Circle Line.

BBC: Revamp for 'oldest' Tube carriage