Irish low-cost carrier Ryanair has confirmed it is to sue the UK government for £3.3 million ($6.2 million) for losses incurred as a result of tighter security measures at UK airports, that were imposed as part of the foiled transatlantic terror plot earlier this month.

Last week Ryanair chief executive Michael O'Leary delivered an ultimatum to the government, claiming a the new restrictions on hand baggage to be barrier to its quick turn-around business model. O'Leary today said the UK authorities had failed to return security to normal. As a result, the airline was losing over £3 million in revenues from UK passengers, since customers would be put off by the carrier's hold baggage charges. "It is a shambles and a cock-up and we are giving terrorists and extremists a victory," O'Leary says.

From mid-August each passenger is permitted to carry a single item of hand baggage through the airport security point. The maximum dimensions of which must not exceed a 450mm length (18.1in), 350mm width and 160mm depth. Ryanair charges passengers flying from the UK with larger bags have to pay €8/kg ($22.50/lb) up to a maximum of 20kg. This restriction makes flights less attractive, O'Leary argues.

Ryanair says it will, if successful, give any payout to charity.