Stelios Haji-Ioannou announced his bus plan in November last year

He plans to complain to the Office of Fair Trading (OFT) that the coach operator is trying to make Easybus unprofitable and is acting illegally.

National Express has denied the allegations, saying that they have been offering cheap fares for 18 months.

Easybus is to begin operating on Thursday in Milton Keynes.

Speaking ahead of a press conference to launch the service, Mr Haji-Ioannou claimed that National Express had abused its dominant position in the intercity bus market by cutting fares.

Price war claim

"What they are hoping to do is make Easybus unprofitable in the hope that we will withdraw the service so that they can put prices up again," he said.

"If this were to happen, it would be consumers who would pay the price.

"I think the regulators should intervene and prevent an unlawful abuse of dominant position so that Easybus can continue to offer low bus fares to more people on an increasing number of routes."

Fares, which are bookable over the Internet, start at �1 one way but are likely to rise in peak periods.

Long-running promotion

A route between Luton Airport, home of Easyjet, the airline which Mr Haji-Ioannu founded in 1995, and Hendon, North London, will be introduced on 13 September to follow the Milton Keynes-to-Hendon route.

A National Express spokeswoman said that, if the OFT does decide to consider the claim, they would defend themselves strongly.

She said: "We offer what are called 'funfares' and have done for the past 18 months across our network.