London's long-awaited all-night Tube service starts on two lines on Friday night after a year-long delay.

The launch was delayed after transport bosses took months to negotiate new contracts with the unions.

The service will run on the Central and Victoria lines through the night on Fridays and Saturdays, from 12.30am to 5.30am, during which period there will be six trains an hour.

Around 100 British Transport Police (BTP) officers will be on patrol across the network.

It will be expanded to the Jubilee, Northern and Piccadilly lines in the autumn.


Image: London Mayor Sadiq Khan in front of a new Night Tube logo at Oxford Circus

Plans for the service were first announced in November 2013 and it was expected to begin in time for the Rugby World Cup in September last year, under former London mayor Boris Johnson's watch.

Current London Mayor Sadiq Khan, who has recorded welcome messages which will be played over the public address system at Oxford Circus, said his predecessor "gave up" on the project.

He said: "It's not me making a cheap point, but the previous mayor did announce the Night Tube start date on one occasion and that wasn't met, on a second occasion, that wasn't met, on a third occasion, that wasn't met, and then gave up.

"My point is TfL staff work incredibly hard. It can't be beyond the wit of a full-time mayor and TfL to make this work properly.

"When I see the enthusiasm from employers in London, investors to London, tourists in London, about the Night Tube, it's surprising it's taken us this long to get it."

Image: Ex-London Mayor Boris Johnson announced several start dates that were not met

He said just two of the five lines were being opened initially because "we don't want a big bang (with) errors and mistakes".

He added: "There may well be teething problems when we first begin but the key thing is to learn from that and to improve upon that before we unveil the other lines later on this year."

London Underground (LU) estimates that 200,000 people will use the all-night service each weekend once it is up and running on all five lines.

Around half a million passengers currently use the Tube after 10pm on Fridays and Saturdays combined.

LU's new managing director, Mark Wild, who launched night services in Melbourne, Australia, earlier this year, said: "It's not just for revellers. It's for the night-time economy - people working in hospitality, shift workers, nurses.

"We expect a nice mix of people who enjoy the fantastic night life of the city, but it's also a lot about giving people mobility."

A recent study by London First, a business membership organisation, estimated the Night Tube could be worth £77m each year to the capital's economy by 2029.