The Channel Tunnel is closed after a fire broke out on a freight train about seven miles into the tunnel from Calais.
The blaze broke out at 2pm said operator Eurotunnel, and all trains have since been suspended. It is thought services will not resume until Friday afternoon.
A lorry carrying phenol, a toxic chemical used by the pharmaceutical industry is understood to have overturned on the train.
The incident resulted in "minor injuries" but no-one was seriously hurt, Eurotunnel officials said. Thirty-two people on board the train were led to safety although 14 people suffered minor injuries, including smoke inhalation.
More than 100 British and French firefighters are at the scene. The incident has caused road chaos on both sides of the Channel, leaving thousands stranded.
Traffic is already stacking up at the British end of the tunnel with queues of lorries and cars tailing from the Eurotunnel terminal at Folkestone. Kent police have closed junctions eight to nine of the coastbound section of the M20 and sections of the motorway have been used to queue lorries as part of Operation Stack.
Chief fire officer Bill Feeley of Kent Fire and Rescue Service said: "The fire itself, because it's in a tunnel, it's in a confined space, produces a lot of smoke and a lot of heat for our firefighters to contend with.
"We're working from one end as the French fire service works from the other, and I know they've been in audible contact, so that's how close they are."
