LONDON — The U.K. is expected to soon announce the winner of a multibillion-pound contract that will end military involvement in the country’s mainland helicopter search and rescue (SAR) operations.

The U.K. Department for Transport (DfT) was due to announce the winner of the SAR helicopter service deal on March 25, but the deal may be announced when the Chancellor of the Exchequer unveils his budget on March 20.

The 10-year contract will see the winner bringing in a fleet of modern new helicopters to provide SAR from 10 bases around the U.K. They will take over from the Royal Air Force and Royal Navy, which have been providing the majority of the service since the end of the World War II.

Two bidders remain in the process: Bristow Group and Bond Offshore Helicopters, which is part of the Avionics Group of helicopter operators.

Several U.K. press reports have suggested that Bristow has been selected to run the entire service. But that has been denied by both the DfT and Bristow. Third bidder CHC was not invited to tender its final bid at the end of 2012 because one of the other contenders had tendered a bid some 20% lower.

SAR helicopter operations are currently carried out by the Royal Navy and the Royal Air Force flying the Westland Sea King and by the Maritime and Coastguard Agency (MCA) using a mix of S-92s and AW139s. They are provided by CHC under an interim contract operating from Portland, Lee on Solent, Shetland and the Isle of Lewis.

The new contracts, announced in 2011, were announced following the abandonment of the 25-year SAR-H private finance initiative after irregularities were found in the bidding process. This forced the government to create a new interim contract.

It was awarded to Bristow to provide SAR capability to Northern Scotland and the Shetland Islands, while CHC retained a deal to continue its work along the South Coast. The first new S-92s for Bristow to be assigned to the Scottish interim contract have arrived in the U.K. and begun training to start flying with the U.K. Maritime and Coastguard Agency (MCA) in the summer.

The decade-long contracts will finally allow the RAF and Royal Navy to focus on front-line operations and enable the U.K. defense ministry to meet its previously announced intention to retire its fleet of Westland Sea Kings in 2016.