The Central Line usually carries about 600,000 commuters a day

Seventeen Central Line trains began running between Bethnal Green and Leytonstone in east London on Friday, the first stage in a phased reintroduction of the service.

Trains are running with speed restrictions at five minute intervals for the first time since the crash at Chancery Lane on 25 January, in which 32 people were injured.

But it is likely to be another month before safety inspectors give the go-ahead for a full restoration of the service, which stretches from West Ruislip in west London to Epping in Essex.

LU and safety experts have been examining the full stock of 85 trains since a motor fell off one Central Line train and hit the track, derailing the train.

Safety brackets have been fitted to catch motors, should bolts work loose again, before they hit the track.

The suspension caused weeks of disruption

Commuters are advised to continue using buses or other forms of transport where possible until the entire service is restored.

LU managing director Paul Godier said he realised it had been a "difficult and exasperating" time for Tube users.

He said: "Our engineers and depot staff have been working around the clock to modify the Central Line trains while at the same time ensuring we are meeting our exacting safety standards.

"While inconvenienced, I believe our customers would not want us to run a service until we were 100% sure that it is safe."

LU has said that if the trains are not overcrowded at the east side, then the west side of the line from Ealing Broadway to Marble Arch will also be opened.