Hard Brexit would deprive UK of vital intelligence and put national security at risk, parliamentary inquiry will warn

Theresa May to be told to drop resistance to EU judges overseeing cross-border flow of data

Britain risks losing access to intelligence sharing through the Europol law enforcement agency, peers will say (Getty)

National security will be put at risk unless Theresa May aborts a hard Brexit that would starve Britain of vital intelligence information, a parliamentary inquiry will warn.

The Prime Minister will be told to drop her resistance to EU judges overseeing the cross-border flow of data or give a helping hand to terrorists and organised crime, The Independent has learned.

Britain must pursue a transitional deal on data-swapping or risk an immediate stop on Brexit departure day in March 2019, an all-party House of Lords committee will say.

Its hard-hitting report will suggest that this can only be achieved by conceding continuing oversight by the European Court of Justice (ECJ) – a red line for Ms May in the Brexit talks, so far.

At stake is access to intelligence sharing through the Europol law enforcement agency and to the Schengen information system, which holds an 8,000-name watchlist of suspected terror suspects.

Without a deal, separate agreements would have to be struck with individual police forces and intelligence services – with the danger that vital information will “fall between the cracks”, experts fear.

The peers will also strongly criticise the Home Office for failing to explain how it plans to avoid a sudden “cliff edge” loss of intelligence, when giving evidence to the inquiry.

The stark warning will carry extra weight because Lord Condon, the former Metropolitan Police Commissioner, sits on the committee and will speak out when it is released on Tuesday.

A source who has seen the report told The Independent: “The committee will say a transitional arrangement is crucial if the Government is not going to put national security at risk.

“It will say it has little confidence that a new deal can be struck in time – so the status quo makes sense, which involves oversight by the European Court of Justice.”

The source added: “The committee was taken aback by ministers’ inability to give any clear direction as to how they intend to deal with this enormously complex issue.”

The report, by the Lords EU Home Affairs Sub-Committee, will warn that security data-sharing with the US could also be lost – because that currently forms part of an umbrella agreement with he EU.

Also at risk is Britons’ control over their own personal and financial data, vast amounts of which is held in the US, rather than in Britain.

The threat arises because, after Brexit, the UK will be treated as a “third country” – requiring the European Commission to be satisfied it will protect data as securely as EU members.

It will take up to three years for Britain to be granted an “adequacy decision” from Brussels – the necessary approval for data to be freely exchanged.

Furthermore, the ECJ has ruled that mass data retention of the kind allowed in the UK under the Investigatory Powers Act, or “snoopers’ charter”, is unlawful, throwing up a further hurdle.

Businesses also fear the loss of data sharing rights. Companies face moving part of their operations to the EU or risk losing business to rival firms on the Continent.

The British Bankers’ Association has warned of a “damaging cliff edge effect” where the flow of data “could lapse overnight at the point of UK exit from the EU”.

Last month, The Independent revealed how technology experts feared ministers were not giving the issue proper priority because they did not understand it fully.

Antony Walker, the deputy chief executive of the trade association techUK, said: “The danger of an ad hoc fix is that things fall between the cracks and, for security issues, that would be a significant risk.

“Ministers say this is on their list of ten priority issues, but I’m not sure they understand the full significance of the threat.”

The Home Office is expected to respond when the report is published, after one of its ministers, Baroness Williams of Trafford, left the committee in the dark when she gave evidence in April.

Baroness Williams was unable to say what “the transition arrangements might look like”, telling peers: “I am not being unhelpful. It is just that I cannot.”

Asked whether Britain was willing to sign up to amendments to data transfer rules after Brexit, to ensure continued compliance, she replied: “I literally do not know. That is to be determined.”

The minister was also unable to say whether anyone from the Home Office would be represented at the Brexit negotiations, to ensure the issue was given prominence.