Passenger services have started running through the Channel Tunnel again following the fire which started on Thursday.

The first test train to run since the closure made a successful journey through the Tunnel late Friday night.

A freight train set off from Folkestone before midnight and was followed by an empty shuttle train.

Eurotunnel said shuttle and Eurostar trains are operating a limited service, with four trains an hour running through the south tunnel.

Eurostar expects to run up to 12 trains each way between London and Paris, up to six trains each way between London and Brussels and the daily service each way between London and Disneyland Resort Paris. Trains will also serve Ashford International, Ebbsfleet and Lille.

The fire broke out in the north tunnel at about 3pm on Thursday.

It was reported that at the height of the blaze the heat built up to 1,000 deg C.

Fire services would not hand over the tunnel to operators Eurotunnel until they were sure it was safe.

Emergency operations at the Channel Tunnel explained

Six people suffered minor injuries after the fire broke out on a freight shuttle. Thirty-two people were led to safety into the service road tunnel, running parallel. Such was the serious nature of the fire, the emergency planning was taken over by BINAT: a combination of national authorities.

It was run from France, as the incident occured on that side.

More than 100 firefighters from Kent fought the blaze at the height of the operation and that was scaled back to 60 yesterday morning.

Chief Fire Officer Bill Feely said the county was well covered, despite the drain on resources.

He said: "We can be absolutely confident as a large part of the planning we do is to put stand-bys and backups in place. This is the sort of incident we plan for. If I wanted to I could call on firefighters from my hometown."

A rota system was used to rotate firefighters away from the fire and inside the tunnel, while keeping stations staffed above ground. Retained firefighters who had experience of exercises in the tunnel were also called in to help.

The first notice of the problem occured at 2.55pm UK time, when a fire alarm went off in the North rail tunnel.

The freight shuttle was carrying lorries in wagons, with 32 drivers in a passenger carriage at the front of the train.

The carriage was evacuated into the service tunnel, a road tunnel that runs between the running tunnels, and French firefighters travelled down the same tunnel to access the blaze.

Passsengers walked from the running tunnels into the service tunnel through cross-passages fitted with air-tight doors.

The service tunnel is pressurised so smoke and flames do not follow people being evacuated – it also keeps it free from smoke.

Jacques Gounon, Chairman and chief executive of Eurotunnel said: "I would like to thank our staff for their swift actions to protect our customers. Eurotunnel is conscious of the disruption caused by this situation and will do all it can to re-establish the best possible service as soon as can be done. Eurotunnel is well-equipped to meet any operational incident and has demonstrated its abilities to respond effectively."

Emergency planning for such a fire is a fact of life for Eurotunnel, which holds regular exercises on how to deal with the danger.

A recent overnight exercise saw the tunnel shut down completely so emergency crews from both sides of the tunnel could work together on a fake ‘incident’.

Fire alarms line the length of the tunnel and are so sensitive that a flashgun on a camera could set them off.

Buried underground in Britain is the Rail Control Centre, where a giant representation of the Tunnel lights up one wall, with trains represented by moving dots of light.

The shuttle still marooned underground will be up there on its own as there is no other traffic left under the sea.

There is a similar centre in France, which used to be back-up but now does the lion’s share of the work.

An emergency room on the French side is filled with banks of fax machines, phones, screens and a magnetic white board with stick-on trains and fire engines easily put in place to represent actions underground.

It’s surprisingly low-tech but it cannot freeze up like a computer.

When an emergency occurs, representatives from the fire service, Eurotunnel and police and the local state all get together in this room. They overlook the French signalling centre and liaise with staff deep underground to plan a solution.

The Service Tunnel, running between the rail tunnels, is airlocked at both ends and along its length, keeping a positive air pressure. This means it will not fill with smoke and will drive flames and smoke away from evacuating passengers.

Fire crews drive down the tunnel on vehicles guided by magnetic ‘rails’ embedded in the concrete. This means they can reverse out at high speed without having to turn round in the tight space.

The screens the signalling staff look at in Britain are replicated upstairs in the Terminal Control Centre, overlooking the traffic waiting to join the shuttles.

During the freight peak period, Tuesday to Thursday, about 5,000 lorries flow through the Tunnel from Britain each day, 30 per train.