Eurostar trains had not undergone sufficient weather preparations, according to an independent report into failures of the service in the run-up to Christmas. Heavy snow storms in northern France saw six trains malfunction in the Channel Tunnel – with as many as 2,500 passengers stranded for up to five hours.

Contingency plans for helping these stranded passengers were also “insufficient” finds the report, commissioned by Eurostar.

A further one hundred thousand passengers experienced disruption over the Christmas period, as Eurostar was forced to cancel all services for three days.

While Eurostar trains undergo a “winterisation” programme during the colder months, the train operator argues snow in France was finer than usual, thus penetrating the grilles on the side of power cars.

Entering the Channel Tunnel warmed the trains, melting the snow and causing electronics to short circuit.

In a statement Eurostar said: “We fully accept that the handling of the disruption was unacceptable and are very sorry for the inconvenience and discomfort that we caused to our passengers.”

The review – chaired by Christopher Garnett and Claude Gressier - set out three key recommendations for Eurostar:

* Train reliability - engineering improvements to enhance the reliability of its trains.

* Evacuation and rescue - improvements should be made to tunnel evacuation and rescue procedures, to ensure passengers can be transported from the tunnel quickly and effectively.

* Managing disruption and improving communication - improvements to assist passengers better and provide more effective communication in times of disruption.

In response the organisation will invest £30 million in improvements to the resilience of the Eurostar trains during severe winter conditions, as well as in passenger care during disruption and customer communication both inside and outside the Tunnel.

Of the £30 million, £12 million has already been earmarked for some time for a new tunnel communications system - but the additional funding is new investment.

Richard Brown, chief executive of Eurostar, explained: “I know we let our passengers down before Christmas and I am determined to put things right.

“Our priority is to win back the confidence of our passengers by taking all the action necessary to prevent this ever happening again.

“Our focus now is on fully implementing the recommendations from the Review as well as those additional measures that we have identified ourselves to improve our service,” he added.