Cross-Channel sailings will be hit by the fishermen's action

The industrial action, due to run from 0730 GMT to 1600 GMT, is likely to block any ferries trying to dock.

The French ports of Boulogne and Dunkirk are also expected to be affected by the dispute over EU quotas.

P&O Ferries said it would run four-hour "mini cruises" into France's waters, allowing passengers to buy items at low French duty rates.

P&O and SeaFrance usually operate 35 sailings a day on the route.

"While a blockade by fishermen may prevent us docking our ships at Calais, we are absolutely delighted to offer a service to day trippers," said a P&O spokesman.

Trains continue

"Time and again militant protesters ruin the travel arrangements of our customers, but this time we're going to pull out all the stops to ensure that those who want to shop at French duty rates can do so."

Passenger and freight services through the channel tunnel from London to Paris and Brussels will not be affected by the strike.

"We're expecting to be very busy carrying cars and, particularly, lorries caught up in the industrial action," said a Eurotunnel spokeswoman.