Eurotunnel, which manages the tunnel link between Britain and France, was criticised Wednesday for an advert claiming its services ran in any weather, after delays caused by heavy snow last year.

Britain's Advertising Standards Authority (ASA) ruled that an email promotion entitled "France in just 35 minutes" and stating this was true "whatever the weather" was misleading and could not be shown again.

The ad was challenged by a customer who was stranded at the Eurotunnel check-in for several hours in December, after five Eurostar passenger trains broke down in the tunnel forcing the suspension of all cross-Channel services.

Eurotunnel had argued that the break-down, which sparked a three-day shutdown of the Eurostar service and left thousands of passengers stranded in the busy Christmas holiday period, was not their fault.

Eurostar was a completely separate company and Eurotunnel trains continued to be able to function, they argued, according to ASA documents.

The firm added that the weather conditions at the time were "very unusual, in the same way that a hurricane or tsunami was" and believed their advertising campaigns need not take into account such "exceptional circumstances".

However, the watchdog said the claim to travel "whatever the weather" suggested the service was unaffected by any intemperate climate, which could not be true as long as it relied on companies -- such as Eurostar -- that were.

"We considered that the conditions of December 2009 could not be placed in the same bracket of exceptional weather as a hurricane or tsunami and it could not be assumed that they would never be repeated," the ruling said.

"It was therefore possible that the weather would again affect Eurotunnel journeys in future. We concluded that the claim had not been substantiated and was misleading."