Boris Johnson today hinted at a delay to the launch of London's new 24-hour tube service.
The introduction of the 'night tube' in September is at the centre of a bitter dispute between London Underground and the unions.
The entire tube network was at a standstill today because of a strike. Hundreds of thousands of commuters struggled to work.
The unions, Aslef, RMT, TSSA and Unite, have rejected a 2% pay offer and bonuses of up to £2,500 for staff working on the night tube.
The new service, on Friday and Saturday nights, is due to start on September 12th but the Mayor admitted the launch date could slip.