7 March 1969: Queen Elizabeth II officially opens the Victoria Line

London's tube system is a marvel to behold. It is the world's oldest – the Metropolitan Railway first opened in 1863, while the first deep line, the City and South London Railway (now part of the Northern Line) opened in 1890. But by the end of the 1940s, the tube was getting congested. A new line was proposed that could relieve congestion in the centre of London, and would run between Victoria and Walthamstow.

A trial tunnel was built in 1959, and construction began in earnest in 1962. The 21-foot diameter tunnels were dug into the buttery clay beneath London by hand. Progress was slow – they managed just over three metres a day. By contrast, the latest tunnel boring machines used in London's newest underground line – Crossrail – managed 38 metres a day.

But by 1 September 1968, the first section between Walthamstow Central and Highbury & Islington was ready to open. There was no ceremony, no pomp; the first train just trundled out of the station at 6:30 in the morning. On 1 December 1968, operations were extended to Warren Street. But by 7 March 1969, the new line had reached Victoria Station. It was time for an official opening.

So the Queen made the short journey from her house in town to Green Park station, where, surrounded by palace flunkeys and the world's press, she “bought” a ticket, rode the escalator down to the platform, and stepped into the cab of a waiting train, which whisked her the two stops to Oxford Circus. It was only the second time she had ever been on the tube. At Oxford Circus, she got out of the cab and returned to Victoria in the train's carriage. At Victoria, she unveiled a plaque. The Victoria Line was officially open. It reached its final destination, Brixton, in 1971.