Boris Johnson has revealed that the Night Tube service on some London Underground lines will begin in July - earlier than previously thought.

Speaking to the Press Association, the London Mayor said he had been given the approximate launch date by Transport for London (TfL).

It comes slightly earlier than the "early August" start date reported by the Evening Standard at the start of the week.

The newspaper said it was understood the service, which will see trains run all night on Fridays and Saturdays, would begin on the Victoria and Jubilee Lines before being extending to the Piccadilly, Central and Northern Lines in September.

Asked if the wait for the night Tube would end in July, Mr Johnson said today: "Well, that's what I'm told by TfL - towards the end of July."

In pictures: Tube strike in London (July 2015) Show all 12 1 /12 In pictures: Tube strike in London (July 2015) In pictures: Tube strike in London (July 2015) London People queue for buses at Stratford station In pictures: Tube strike in London (July 2015) London Commuters crowd on a platform as they wait for a train on the c2c line at Upminster station In pictures: Tube strike in London (July 2015) London Metropolitan Police with crowds of people queuing for buses at Stratford station In pictures: Tube strike in London (July 2015) London People queue for buses in Stratford In pictures: Tube strike in London (July 2015) London People queue to get on a bus outside Victoria Station In pictures: Tube strike in London (July 2015) London A long line of people waiting at a bus stop in Wimbledon, south west London, as tennis fans leaving the All England Club faced a difficult journey home due to a tube strike In pictures: Tube strike in London (July 2015) London People wait in line for taxis in Wimbledon In pictures: Tube strike in London (July 2015) London A closed entrance to Stratford underground station, as commuters face travel misery trying to get to work because of a strike which has brought London Underground to a standstill In pictures: Tube strike in London (July 2015) London District Line tube trains parked at the Upminster depot during a 24-hour walkout of London Underground staff In pictures: Tube strike in London (July 2015) London Commuters try to board a tube train at Westminster station as workers across the British capital begin a 24-hour strike on 7 July In pictures: Tube strike in London (July 2015) London Commuters crowding around one of the entrances to Oxford Circus Tube station, the rush hour on 7 July started early in London as commuters left work to beat a Tube strike In pictures: Tube strike in London (July 2015) London Commuters crowding around one of the closed entrances to Oxford Circus Tube station. Picket lines were mounted outside stations by members of four trade unions involved in a 24-hour walkout in a row over the new all-night Tubes, due to start in mid-September

Mr Johnson made the announcement as he took the controls of a training simulator being used by some of the 200 part-time drivers who will run the service.

The night Tube was due to start last September but its introduction was delayed because an agreement could not be reached with trade unions.

Referring to the delay in introducing the all-night service, Mr Johnson said: "We've had to go a bit slower than I necessarily would have wanted, but on the other hand better to do that ... I thought Londoners would rather wait a little bit than we pay an exorbitant demand to get it done."

At the beginning of March, TfL and the RMT union agreed a deal to avoid further strikes and pave the way for the Night Tube to be implemented in the summer.

The RMT executive announced its backing for a deal that included a 2 per cent pay rise in year one, RPI inflation or 1 per cent (whichever is greater) in years two and three, and RPI plus 0.25 per cent or 1 per cent in year four, plus a £500 bonus for staff on lines where the night Tube will run.

TfL confirmed that an earlier offer of an additional £2,000 "transition" bonus for train operators at depots where the Night Tube is scheduled to run, on the table last summer, has since been dropped.

All station staff will, however, get an additional £500 bonus "for the successful implementation of the new staff model" - meaning up to £1,000 for keeping the stations open all night.