Mr O'Leary calls for a return to normal measures

O'Leary news briefing

The budget airline says a larger cabin baggage allowance and fewer passenger body searches would avoid handing "extremists an enormous PR victory".

The "no frills" airline prefers to put less luggage into plane holds to maintain its low prices.

The government said it would not pay compensation or "compromise security".

A spokesman at the Department for Transport said the government does not believe it has to pay compensation under the law.

The DfT said on Friday: "The security regime in place at UK airports is necessary because of the level of security threat and is kept under constant review.

"We have no intention of compromising security levels nor do we anticipate changing our requirements in the next seven days."

The best way to defeat terrorists and extremists is for ordinary people to continue to live their lives as normal

Ryanair chief executive Michael O'Leary

'Plot' inquiry spanning UK Curbs spook budget airlines

The DfT spokesman added that the restrictions were introduced under the Aviation Security Act of 1982, which allows the government to implement measures for the safety and protection of the public.

Ryanair has threatened to claim compensation under a different act - the provision of section 93 of the Transport Act 2000.

Meanwhile, Virgin says it will discuss the cost of extra airport security staff with BAA.

Virgin said it was "not seeking compensation from the government", but thought it should pay for the staff.

Ryanair is keen to encourage more customers

Ryanair chief executive Michael O'Leary described the situation at London airports after the security measures were imposed last Thursday, as a "shambles".

He said: "If they allow these restrictions to stay in place, then the government will have handed the extremists an enormous PR victory."

Demands

In launching a campaign to "get Britain flying again" included one million seats for sale on more than 100 routes, priced at £25, one way, including taxes and charges.

The measures the airline has demanded include:

Restoring the hand luggage allowance for passengers leaving British airports to the normal International Air Transport Association (IATA) dimensions of a small, wheeled case, which is just 20% larger than the current restriction of a "large briefcase" dimension