A fresh row over cuts on London Underground flared today as union leaders said commuters suffered the "rush hour from hell" because of fresh delays to services.
The Waterloo and City Line, used by workers in the City of London, was suspended, while a signal failure disrupted the Victoria Line and the Jubilee Line was hit again by disruption.
London mayor Boris Johnson asked for a report to be on his desk by the end of Friday after the Jubilee Line was hit by severe disruption, capping what unions said was the worst week of delays so far this year on the Tube.
Bob Crow, general secretary of the Rail Maritime and Transport union, said this week started where last week left off, adding that commuters suffered the "rush hour from hell" today.
"On Boris Johnson's watch, the Tube has become a sick joke that is failing hundreds of thousands of passengers on a daily basis and yet he has the nerve to tell us to accept more job and maintenance cuts.
"The Jubilee Line is a shambles as privatisation has cost us hundreds of millions of pounds for a pig in a poke system that simply doesn't work and probably never will. That's a financial scandal of epic proportions."
Gerry Doherty, leader of the Transport Salaried Staffs Association, said: "Boris Johnson is presiding over a Tube system which is descending into daily chaos for millions of passengers.
"It is not too late to sit down with us and reverse his slash and burn plan which has seen over 7,000 hours a week cut from ticket office opening times and hundreds of Tube jobs go.
"These are politically-motivated cuts to boost Boris's appeal to the Tory right and his long-term ambition to replace David Cameron in No 10. He should be ashamed of himself for playing politics with the Tube in the run-up to the Olympics."
The two unions are locked in a bitter row with London Underground over hundreds of job losses at ticket offices which led to a series of strikes last year and remains unresolved.
The unions and opposition politicians have also criticised reductions in ticket office opening hours, which came into effect yesterday.
London Underground (LU) insists it is improving efficiency and responding to changing sales trends, in particular because of the success of the Oyster pre-pay card system.
A Transport for London spokesman said: "There were severe delays on the Jubilee Line earlier this morning following signalling issues with two trains - one at St John's Wood and one at Dollis Hill. We worked to resolve this as soon as possible and the Jubilee line is now running with good service again.
"The Victoria Line was suspended earlier this morning between Highbury and Islington and Brixton due to issues with the signalling system. This was resolved by around 7.30am, with services now running along the whole length of the line with some minor delays. It is now running a good service.
"The Waterloo and City line was suspended at 7am so that excessive dust left by engineering works could be cleared. We're working to restore services as soon as possible.
"We are working hard to upgrade the Tube, which will mean faster, more frequent trains for passengers. We also continue to focus minute by minute and day by day on improving reliability across the Tube network."