Home Secretary Amber Rudd said Britain was the argest contributor to Europol

Europe will be more vulnerable to terrorism and organised crime if Britain is refused a significant trade deal, it was claimed last night.

Europol, the EU policing agency, will lose access to the UK’s world-class intelligence and policing capabilities if there is no agreement, the Government warned.

Security chiefs in Brussels will be worried because Britain is one of the biggest contributors to the global fight against crime, including extremism, people-trafficking and cyber-crime, and other nations rely on UK intelligence.

Concerns about losing Britain’s expertise have grown in the wake of terrorist attacks in France, Belgium and Germany, and last week in London.

Home Secretary Amber Rudd told Sky News: ‘We are the largest contributor to Europol, so if we left Europol then we would take our information – this is in the legislation – with us.

‘The fact is the European partners want us to keep our information in there, because we keep other European countries safe as well.’

Prime Minister Theresa May, in her letter to European Council president Donald Tusk triggering Article 50, warned: ‘With Europe’s security more fragile today than at any time since the Cold War, weakening our cooperation would be a costly mistake.’

In the Commons, Mrs May invoked the horror of last Wednesday’s attack in London. She said: ‘In an increasingly unstable world, we must continue to forge the closest possible security co-operation to keep our people safe.’

HOW DO NATIONS COOPERATE? EUROPOL Assists member states in the fight against serious international crime, terrorism, cyber-crime, people-smuggling and drug-trafficking. EUROPEAN ARREST WARRANT Speeds up extradition of suspects or convicts between EU nations. PASSENGER NAMES States gather all the information travellers give airlines so they can check for links to terrorism or other crimes. SIS II Has details of 250,000 wanted or missing people. Issues alerts on fugitives, missing people, stolen goods, suspected jihadists. ECRIS Database listing EU citizens’ convictions. PRUM Gives access within 15 minutes to Europe’s DNA, vehicle registration and fingerprint records. Advertisement

Europol is one of a number of bodies that have fallen under scrutiny in the wake of the EU referendum.

Britain is currently a full member but 19 other nations – including the US – have struck operational agreements to share information.

Senior policing figures also highlighted the role played in their work by the European Arrest Warrant and the European Criminal Records Information System, which lists EU citizens’ convictions.

Liberal Democrat leader Tim Farron blasted Mrs May’s ‘scandalous’ letter as a ‘blatant threat’ to the EU.

He said: ‘It is shameful that she has threatened to withdraw security co-operation from our closest neighbours.

‘She is prepared to put the safety of British and European citizens on the line just so she can deliver her hard Brexit.

‘Security is too important to be used as a bargaining chip and this will backfire in any negotiations.’

Rob Wainwright, Europol’s British director, admitted the agency would face a ‘significant detriment’ if the UK left.

Richard Walton, former counter-terrorism chief, said the UK would be in a stronger negotiating position if it withdraws from Europol. He said withdrawing would have ‘little or no effect’ on Britain’s own ability to maintain security, but ‘represents a risk to the safety’ of other member states and that they will therefore continue to seek access to the UK’s intelligence post Brexit.

Last month Lord Carlile, a former independent reviewer of terrorism, said: ‘They need us more than we need them.’

Last night on BBC1’s Brexit – What Next? interview with Andrew Neil, Mrs May warned our membership of Europol will be ‘part of the package of negotiations’. However she insisted she wanted to ‘continue that degree of cooperation’ with the EU on security.