LONDON (Reuters) - A British satellite navigation system to rival the European Union’s Galileo project could be up and running in four to five years and would cost about 3 billion pounds ($4 billion), one expert estimated on Wednesday.

Prime Minister Theresa May asked for options for a British alternative to the Galileo project earlier in May, in response to a row over EU attempts to restrict Britain’s access to sensitive information after Brexit.

Colin Paynter, managing director of Airbus Defence and Space UK, told a committee of UK lawmakers that it was technically feasible for Britain to develop an alternative and that if the country stayed close to the Galileo solution it would cost towards the lower end of a 3-5 billion pound range.

He said the cost estimate depended on exactly what the requirements would be and added that the time estimate of four to five years was helped by the 10 to 15 years of learning from developing Galileo.

“My understanding is it’s (the requirement) not to replicate the entire system, it’s actually to look at giving access to the UK to what is known as the public regulated system, which is a higher reliability and secure signal which can be used by (emergency) services or the armed forces,” Paynter said.

Airbus, the European planemaker, has carried out a substantial portion of work on Galileo through its UK arm. It is Britain’s biggest space company and the majority owner of SSTL, a Surrey, England-based company which makes satellites for the Galileo project.

But the UK arm of Airbus and other British companies are now being locked out of future work on Galileo ahead of Britain’s exit from the EU in 2019.

Paynter said that as a result, Airbus’s latest bids would mean moving work out of the UK, where it has been operating the ground control system for the program for the last 10 years.

“That is a condition of the tender process and effectively that means for Airbus to bid and win that work we will have to novate (move) all that work from the UK to France and Germany on day one of that contract,” he said.