Britain's Civil Aviation Authority has given the go-ahead for Ryanair's Buzz subsidiary to resume flights from Thursday.

The regulator yesterday issued the aircraft operations certificate required to allow the slimmed-down operation begin flying again as planned from May 1st.

Ryanair still requires approval of its deal with Dutch carrier KLM to buy the troubled low-cost airline but this is expected in the coming days. Sources close to the Irish group said OFT approval was not essential to the resumption of services by Buzz from London's Stansted airport.

The OFT could still refer the takeover to the British Mergers and Monopolies Commission.

Mr John Osborne, chief executive of Buzz Stansted Ltd, said he was delighted the airline had secured its vital operating licence.

"We would like to thank the Civil Aviation Authority for all their help and assistance in securing the future of Buzz Stansted," he said.

He also praised the efforts of the group's dramatically reduced workforce in getting Buzz ready to start flying again.

The airline will initially operate on 11 routes to Germany, France and Spain and Mr Osborne said demand to date had been "phenomenal" with more than 130,000 passengers booked to fly in May.

Buzz, which posted cumulative losses of €60 million over the last two years, was sold by KLM for €20.1 million - €3.8 million less than the price originally agreed in January. The deal was concluded earlier this month after Ryanair secured staff backing for plans that saw it take on 130 of the 600 workforce and 10 of its 12 aircraft.

Ryanair had threatened to close down the airline altogether if it failed to secure the necessary redundancies in the face of initial union opposition, citing weekly losses of €1 million as unviable.