Fierce price wars are to keep on raging on the cross-Channel route as P&O Ferries vows to fight new competition.

The DFDS/LD Lines consortium is about to launch a single ship operation on the Dover-Calais route to replace SeaFrance, which went into liquidation last month. A second ship may be added later.

The decision came as P&O launched its latest superferry, the 47,000-tonne Spirit of France, which made its inaugural crossing from Dover to Calais yesterday.

The operator has invested more than £300m in the Spirit of France and its sister ship the Spirit of Britain, launched last year.

The new ferries are more upmarket than previous ships and aim to raise the experience for freight and leisure customers.

One passenger said it was more like a cruise ship, "a floating restaurant and hotel".

Helen Deeble, the Dover-based operator's CEO, said fares were still relatively low (£30 each way for a car and up to nine passengers) and cheaper than a train ticket from Dover to London.

She said the operator intended to maintain and increase market share - it is the largest ferry operator on the short-sea route, although Eurotunnel has the biggest overall market share.

"We intend to fight and be competitive on every front possible," she said on board the Spirit of France. "We wait to see what DFDS will do with a one ship offer or a two-ship offer.

"We will ensure we offer value for money to the consumer. If that means competing head to head with them on prices, we will do it."

Ms Deeble, who becomes the first woman president of the UK Chamber of Shipping next month, said freight traffic had not grown at the rate expected when the decision was taken to order the two ferries.

But freight traffic formerly carried by SeaFrance had boosted business and there were signs that leisure traffic was switching from airlines to ferries.

She said: "But the tourism market as a whole is relatively flat and we expect this to continue for the next couple of years."