The government refuses to say whether Brexit will further expose the UK to terror attacks
- MPs on the Intelligence and Security Committee asked for an assessment of national security risks linked to Brexit.
- It came after MI5 and GCHQ warned of the value of European security co-operation.
- If this lapses, the UK could become more vulnerable to attacks by terrorists.
- The Cabinet Office declined to give a detailed report.
LONDON - The government has refused to explain to MPs whether Britain's departure from the European Union will weaken national security and make the country more vulnerable to terrorist attacks.
Members of Parliament's Intelligence and Security Committee (ISC) made a formal request for an assessment of the national security implications of Brexit, but were rebuffed by officials.
Members of the committee worry that Brexit could lessen the ability of agencies like MI5, MI6 and GCHQ to defend the UK from threats, including terrorism.
EU member states co-operate in areas like data-sharing, border policing and law enforcement, which can enable them to identify, locate and act against attackers.
According to the committee's annual report, officials from MI5 said that a bad Brexit deal could "affect our ability to operate" in Europe and that GCHQ said there are "big implications" for their work related to Brexit.
The committee said they asked both agencies to expand on these risks, in the form of "a written assessment of the potential national security implications of Brexit" - but that they were blocked from doing so because of the political sensitivity of Brexit.
MPs instead asked the Cabinet Office, which oversees the security services, but had their request turned down.
They criticised the government for its lack of response, saying: "We urge the Government to be more forthcoming with its assessment of the associated risks of the UK's impending departure from the European Union, and the mitigations it is putting in place to protect this vital capability. "
The ISC meets in secret, and only provides an account of its activity in heavily redacted form.
The 2016-2017 report was published in late December, and covers the timeframe to April 2017.
Business Insider contacted the Cabinet Office for comment, which said it had not granted the request because it goes beyond the ISC's remit - a point which the committee disputed. A statement added: "The Prime Minister has made clear that the UK will remain unconditionally committed to maintaining Europe's security."
European and British officials have repeatedly said that they are keen to continue close security co-operation after Brexit, which the ISC report also acknowledged.
However, recent statements from the European Union, including the assertion that Britain will be expelled from the Europol police agency, have raised the prospect that security co-operation could become harder in future.
During the EU referendum campaign, Theresa May herself argued that Britain would be "less safe" outside of European security arrangements.
She concluded: "My judgement, as Home Secretary, is that remaining a member of the European Union means we will be more secure from crime and terrorism."
The back-and-forth over the ISC's request follows a similar pattern to an argument over assessments of the economic impacts of leaving the European Union.
The government produced the papers internally, and tried to keep them secret, but was eventually forced to publish them.