(Reuters) — Britain’s financial sector could lose up to 75,000 jobs as banks and insurers shift operations to the European Union after Brexit, Bank of England Deputy Governor Sam Woods said on Wednesday.

Mr. Woods told British lawmakers that the 65,000 to 75,000 estimate was drawn up in a report from consultants Oliver Wyman, a unit of Marsh & McLennan Cos. Inc., and not the Bank of England.

“I would say in terms of a long-term possibility among one of many scenarios, I regard that in the plausible range of scenarios,” Mr. Woods said.

Banks and insurers have submitted plans to the Bank of England detailing how they would cope if their current level of access to the E.U. market ends in March 2019 when Britain leaves the bloc, and there is no subsequent transition period.

“In that context...I would say ‘Look, it’s a moving feast and we won’t know until we get there’ but you could reasonably think of a day-one movement of perhaps around 10,000,” Mr. Woods said.

“I would be surprised if it ends up being more than that for banks and insurance companies... That’s 2% to 3% of the City," Mr. Woods said.

The trading deal struck between the E.U. and Britain will be the key determinant on long-term job moves, said Mr. Woods, who heads the Bank of England’s banking supervision arm.

Financial firms operating in Britain who want to strengthen or set up a hub in the E.U. will start implementing their Brexit plans in the first quarter, Mr. Woods said.

Some banks have already reserved school places in E.U. countries and let office space.

This meant it was important for the U.K. government and the E.U. to agree a transition deal “the sooner the better” given that it was a “wasting asset,” Mr. Woods said.

Without a transition deal agreed by the start of 2018, the Bank of England will have to begin reauthorizing 75 banks and 85 insurers from the European Economic Area, Mr. Woods said.

British bank Barclays P.L.C. said on Wednesday it was having to put in place Brexit plans without political clarity.