"It is a matter of trade off and choices, and nothing will be as it was before, all will change, we have to accept that fact," von der Leyen said during an event at the London School of Economics.
Banking makes up the biggest part of Britain economy, but she said there needed to be difference to the rules that apply to EU member states and those not in the bloc.
"A very important field, financial services, there too, all will change," she said.
(Reporting by Marc Jones; editing by William James)
