LONDON (AP) — London’s police chief has suggested that Brexit will be costly and could have a damaging effect on public safety.

Cressida Dick told the BBC on Thursday that leaving the European Union would be more challenging if there’s no deal in place between Britain and the bloc.

She said that U.K. police will have to work out access to vital databases and need new procedures so people can still be quickly arrested and extradited despite Brexit. Dick said that would be “very difficult to do in short-term” if Britain has no transition deal.

Dick hopes Britain will have systems like the ones in place now to facilitate fighting crime.

Prime Minister Theresa May has agreed upon a Brexit deal with EU leaders but many British lawmakers don’t like it.