Met police chief raises concerns about Brexit impact on security measures

She added there would be cost and public safety consequences of having to replace such systems.

Prime minister Theresa May has insisted her Brexit deal protects security although MPs have raised concerns over the level of UK access to European security measures.

Asked about a no-deal Brexit, Ms Dick said the UK worked closely with the EU at the moment.

She told BBC Radio 4’s Today programme: “If we come out without immediately obvious replacements for those instruments, that will undoubtedly mean we will have to work incredibly hard on a bilateral basis with countries to try to get in place some kind of way of working together.”

Ms Dick said talks were ongoing, adding: “We’ve set up an EU coordination unit, absolutely.

“That is to help local forces to understand to how to work most effectively across Europe after we exit the EU, under whatever circumstances.

“Of course, we would hope we will have as much as possible of the instruments we currently have or something very similar as quickly as possible in order to be able to keep our public safe and at the same sort of cost.”

Told she was suggesting the consequences of not having such a situation would mean the UK was less safe, Ms Dick replied: “The consequences are that we will have to replace – and of course if there was a no-deal scenario that would be very difficult to do in short-term – some of the things we currently use in terms of access to databases, the way in which we can quickly arrest and extradite people, these kind of things, we will have to replace as effectively as we can.

“That will be more costly undoubtedly, slower undoubtedly, and potentially yes put the public at risk – no doubt about that.

“But I understand that this is just one of many things that the politicians who are deciding what to do next have to think about.”

Former home secretary Jacqui Smith, a leading supporter of the People’s Vote campaign for a second EU referendum, said: “Cressida Dick is right to warn about the security risks of Brexit, but it must be clear to her and everyone working in our police and security services that leaving with the government’s deal would not address those risks. It would be a huge mistake for anyone to think otherwise.

“The reality is that the government’s plan will weaken UK participation in the European Arrest Warrant, making it harder to tackle cross-border crime, and offers no long-term guarantees at all of access to vital security databases.

“From a security perspective, by far the best option would be to go back to the public in a People’s Vote with the option of keeping our current deal as EU members. That would keep the European Arrest Warrant and all database access and allow the UK to continue working with our European partners to keep the public safe.”

Liberal Democrat MP Layla Moran, a champion of the anti-Brexit campaign group Best for Britain, said: ‘It doesn’t matter whether you voted to leave or to remain, you certainly did not vote to be less safe. Yet now we know Brexit will do just that. ‘The UK’s top police officer is only echoing what we’ve heard from police forces across the country: that Brexit threatens the ability of police to catch criminals. No one can argue that would make us better off than if we stay in the EU. ‘Continuing along these dangerous lines is criminal. The public need the final say on Brexit, with the option to stay and pool our safety with the rest of Europe.’