How experts at GCHQ defend the continent

EUROPE would be more vulnerable to terrorism and organised crime without Britain’s intelligence expertise.

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

In GCHQ, MI5 and MI6, Britain has one of the most effective antiterrorist networks and powerful surveillance systems in the world.

Senior policing figures have 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. Rob Wainwright, Europol’s British director, has previously admitted the agency would face a ‘significant detriment’ if the UK left.

Meanwhile, Richard Walton, former counter-terrorism chief, 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. He predicted they will therefore continue to seek access to the UK’s intelligence post Brexit.

Spending on counter-terrorism and the security and intelligence agencies – MI5, MI6 and GCHQ – will be £15.1billion by 2020-21.