Sam Woods, Britain’s top banking regulator, said a consultancy’s estimate that Brexit could cause as many as 75,000 job losses in banking and insurance is “plausible” if the U.K. leaves the European Union without a trade deal.

About 10,000 U.K.-based jobs are probably at risk on “day one” of Brexit, Woods, chief executive officer of the Bank of England’s Prudential Regulation Authority, told lawmakers in London on Wednesday, citing firms’ responses to the PRA’s inquiries about contingency plans.

“In terms of a long-term possibility amongst one of many scenarios, I regard that as within the plausible range,” Woods said of Oliver Wyman’s estimate. “It’s a moving feast and we won’t know until we get there, but you could reasonably think of the day one movement as perhaps around 10,000. I would be surprised if it ends up being more than that for banks and insurance companies.”

Oliver Wyman reached its estimate by looking at the portion of total revenue the U.K. obtains selling financial services to the EU and hypothesizing a decline of 40 percent to 50 percent in that part, Woods said. Oliver Wyman estimated that as many as 35,000 jobs could be at risk in its “lowest-access scenario,” with as many as 40,000 potential additional losses from “the knock-on impact” on the financial-services industry.

Woods, accompanied in the House of Lords hearing by BOE Deputy Governor Jon Cunliffe, said he expects firms to start putting contingency plans into operation in the first quarter of next year.

Financial firms will need time to adjust to whatever arrangement the government and the EU reach, Cunliffe said. He added that he expects them to have to review their business models once the nation’s withdrawal is complete.