London Underground travellers suffered fresh delays and disruption today because of cracked and defective rails, continuing a week of "chaos" on the Tube.
The Jubilee Line - used by more than 500,000 passengers a day - was suspended through central London from the start of services this morning because of a cracked rail, with other lines becoming packed as commuters switched to different routes.
The Metropolitan Line was later suspended for over 30 minutes because of a defective track, causing more problems for commuters and other travellers.
The new delays followed a public apology by London Underground (LU) managing director Mike Brown for problems caused earlier this week.
Thousands of passengers suffered major disruption after being forced to walk along the tracks through darkened tunnels from stranded trains on two lines on Monday and Tuesday.
Bob Crow, general secretary of the Rail Maritime and Transport union, said: "Once again today the transport system in London has been reduced to chaos with a cracked rail on the Jubilee Line this morning and another major failure on the Metropolitan line this afternoon.
"It is now absolutely clear in this week of Tube chaos that the planned 2,000 job losses and the additional government cuts of £2.2 billion will plunge travellers even deeper into the black hole of unsafe and unreliable services.
"The Mayor, who is responsible for transport in this City, appears to have gone Awol and his officials at Transport for London have now resorted to bare faced misinformation and distortion when it comes to admitting the scale of the shambles that has developed on their watch."
An LU spokesman said the Jubilee Line was suspended between Finchley Road and Waterloo due to emergency engineering work in the Green Park area.
"A cracked rail was identified during our routine maintenance check and we are working to rectify the problem as quickly as possible. We apologise for the inconvenience caused.
"The Metropolitan line was suspended between Wembley Park and Finchley Road southbound only from 14.25 due to a defective track in the Wembley Park area. Engineers were called to rectify the problem and services resumed at 14.56. We would like to apologise to customers for any inconvenience caused."
Members of the RMT and the Transport Salaried Staffs Association are due to take two days of strike action next month in a row over job cuts, which would cause massive disruption to services.
The unions have already held two strikes and are pressing ahead with plans for the next walkouts unless talks at the conciliation service Acas lead to a breakthrough in the deadlocked dispute.
Mayor Boris Johnson, speaking about the comprehensive spending review, said yesterday: "I hope very much that London Underground employees listening to the announcements will be immensely heartened that we have a mayoralty and Government that is absolutely committed to investing in a Tube.
"That is of vital importance to them and to this city. I think that the issues around the ticket offices and industrial action we have seen in recent weeks is completely separate to that.
"This is to do with a discrete issue around a necessary programme of reforms that is dictated by the Oyster card system and the greater and different ways people travel.
"It is something we are determined to see through and I hope the leadership will come to the table and do the deal that is there to be done."