(Reuters) - The Bank of England said a transition period after Britain leaves the European Union would give banks more time to make orderly changes as Brexit poses risks to financial stability.

With U.K. due to leave the bloc in March 2019, the Bank of England’s Prudential Regulation Authority said it faces heavy demands from Brexit fallout on banks and insurers.

Bank of England Deputy Governor and PRA Chief Executive Sam Woods said, “some form of implementation period is desirable” between Britain leaving the bloc and start of new trading terms to “give U.K. and EU firms” more time to make necessary changes.

But he stopped short of saying what sort of transition he wanted in a reply to Nicky Morgan, new chair of parliament’s Treasury Select Committee, who asked him this month for his views on the design of such a period.

The British government has not presented the EU with any firm request for a transition period as it still seeks internal consensus.

United Kingdom-based firms are not waiting for clarity and are announcing new hubs in the EU27 to be sure of serving customers there after March 2019 - and avoid the destabilizing ruptures in financial links the BoE fears.

Mr. Woods had asked banks to spell out how they would cope in particular with a “hard” Brexit where Britain crashes out of the EU with no transition or trading deal.

In a letter to Ms. Morgan made public on Wednesday, he said 401 responses were received, which revealed “significant issues for many firms” and the Bank of England will reach a view on the plans in the autumn.

The submissions provided “further evidence” of risks already identified, specifically relating to the continued servicing and performance of existing contracts and restriction on data transfers.

There could be a sharp rise in the number of insurance policies shifted from one country to another, a switch that involves the courts, he said.

The Association of British Insurers said insurers fear they will be left with a stark choice between breaking their promise on millions of policies with customers, or breaking the law regarding payouts on cross-border contracts still in force after Brexit.

“Agreeing terms to allow insurers to service contracts after March 2019 needs to be part of the exit negotiations between the U.K. and EU,” said Huw Evans, director general of the ABI.