The train and tunnel wall were badly damaged in the crash

Pictures released by London Underground (LU) on Tuesday show the extent of damage to a train, tunnel wall and equipment caused by the crash at Camden Town station in north London.

There are no Northern Line trains running from East Finchley to Euston and between Golders Green and Charing Cross - rail replacement buses are ferrying thousands of passengers to affected stations.

LU managing director Tim O'Toole apologised for the disruption but added: "We must be assured of the safety of this section of the line before we resume running trains through it.

"Until I have that assurance from Tube Lines and from my own engineers, we cannot restore the train service."

Sales down at Camden market

The closure of Camden Town station has hit stall holders on the Buck Street Market where some say business is 50% down.

Philomena Card, who sells T-shirts from her stall, told BBC News Online: "If it's going to be like this for a whole week it will be desperate.

"Some stall holders are already talking about laying off staff."

Seven people were taken to hospital and more than 200 had to be led to safety when a carriage derailed and hit the wall as a train pulled into Camden Town on Sunday.

The crash happened less than 48 hours after a derailment near Hammersmith, in west London.

We are extremely lucky that the derailment did not cause any loss of life Ken Livingstone, London mayor

Mayor of London Ken Livingstone has called together union leaders and the private companies in charge of maintaining the Tube for a safety summit to try to stave off a drivers' strike.

The Rail, Maritime and Transport union (RMT) has given Tube bosses until Friday to answer its safety concerns or face a strike ballot.

The Health and Safety Executive (HSE) will examine the track and trains as part of its investigation.

Initial findings suggest a broken rail caused the Hammersmith derailment while the Camden incident took place over a set of switching points.

At a news conference on Tuesday, Mr Livingstone said: "We are extremely lucky that the derailment did not cause any loss of life.

"We have an absolute commitment that the Tube must be as safe as is possible."

A report into the Camden derailment is expected by the end of November and another into the Hammersmith incident within three weeks.