Eurotunnel said a CO2 sensor had triggered an alarm, setting off an emergency procedure in which all passengers have to be evacuated.

Eurostar, which runs high-speed trains through the tunnel between London and Paris and Brussels, said its services had been suspended for a period.

Lines have since started to reopen, but passengers were told to expect delays.

Dover Calais Ferries have plenty of spare capacity at present, after having coped very well with the additional passengers following air line disruptions caused by the volcanic ash cloud.

“The traffic is resuming now, we have received authorisation from Eurotunnel,” a Eurostar spokeswoman told AFP news agency. “But we expect a knock-on effect on the schedule.”

Services in both directions were halted when the alarm was triggered in the tunnel shortly after 0700 BST (0800 GMT).

The nearest train, a shuttle carrying 30 lorries and drivers, was evacuated and taken back to the surface on the UK side.

Emergency services from Kent were called.

Nigel Shamber, duty inspector at Kent Police, said: “They have an awful lot of sensors in the tunnel and one of them went off. These things happen very frequently.

“There has not been a fire or any significant incident. Trains are now running in a reduced capacity.”

A Eurotunnel spokeswoman said: “The freight train was travelling towards England and was more than half-way through the tunnel when it was stopped.

“Emergency services are trying to work out why the detector went off. We need to understand why it happened.”

Nine Eurostar trains were delayed by between 50 minutes and three hours, French state rail operator SNCF said. Services leaving Paris, London and Brussels were all hit.

Technorati Tags: Calais, channel, Dover, dover calais ferries, Eurostar, Eurotunnel, ferries, Kent, London, Paris, shuttle

Information on how to get back to the UK if you are stranded in Europe due to volcanic ash flight disruption.

You should continue to make your way directly to Calais, other Channel ports and other northern European ports.

In addition to the Eurostar services to the UK from Paris and Lille, travellers arriving at Channel ports in France by road or rail are advised that ferry companies on the Dover Calais route and other cross channel ferries are able to accommodate foot passengers.

For further official advice see Foreign and Commonwealth Office

Technorati Tags: ashtag, Calais, cross channel, cross channel ferries, disruption, Dover, europe, Eurostar, ferry, foot, Lille

You can take a ferry from Dover or Folkestone to Calais or Boulogne. Prices vary, but Speed Ferries seem to be the cheapest. With Eurotunnel as well as the ferries, the less time you spend in France, the cheaper the crossing.

“Peages” are toll autoroutes. From Calais to Paris it’s about 10 euros one way. Plus you have to pay for petrol. So travelling to France by car can be quite expensive any way you look at it. You can take non-toll roads (“nationals”) but it will take you longer as you pass through villages/traffic lights, etc. and the speed limits are lower (the limit on peages is 130k/83miles per hour).

Eurostar does specials on occasion which work out to be much cheaper than driving to Paris for one to three passengers. Plus, you are in central Paris and don’t have to worry about parking or having your car vandelised/broken into, which has happened to me a couple of times!

Technorati Tags: autoroutes, boulogne, Calais, car, central paris, crossing, Dover, england, Eurostar, Eurotunnel, ferry, ferry from dover, folkestone, france, Paris, toll roads, tolls, travelling to france