P&O ferry Pride of Calais arrives at the Calais' harbour, northern France, on January 2, 2012, with the white cliffs of Dover in the background. Acquired by Ports, Customs and Free Zone Corporation of Dubai in March 2006, the Peninsular & Oriental Steam N / PHILIPPE HUGUEN/AFP/Getty Images

Operation to remove two Second World War German mines found on a beach near the port means that the channel crossings will be delayed

The French port of Calais is closed this morning, affecting the main ferry link between the UK and Continental Europe: from Calais to Dover - which normally handles an average of 30,000 people a day.

The port is partially closed because of the need to remove two Second World War German mines that have been found on a beach that extends from a headland just east of the port. The operation that got under way at 6am British time.

A 1,500m exclusion zone has been put in place. It does not extend to where ferries dock, and there will be some sailings docking from Dover during the operation - with arriving motorists routed away from the exclusion zone. But it does cover the UK Border Agency posts that check cars and lorries heading for Dover.

As a result there will be no sailings to Dover on P&O Ferries, MyFerryLink or DFDS for around seven hours. The leading ferry line, P&O, is urging day-trippers to postpone their journeys, and is offering free transfers to people who want to switch sailings to this afternoon.

Car drivers who turn up at Calais will be re-directed to a sports centre to wait for ferry services to resume, while trucks will be held on the A16 motorway outside Calais.

Eurotunnel, whose Shuttle operations between Folkestone and Calais are unaffected, will be laying on extra services.