‘Where are the contingency plans when our police forces find themselves unable to check the databases of 28 EU countries at the touch of a button?’

Delivering a major speech on the threats posed by Brexit, Mr Clegg is expected to say: “How will Britain be kept safe after Brexit?”

“Theresa May has vowed to pull Britain out of the jurisdiction of the European Court of Justice, a decision which means we would no longer have access to vital EU-wide databases of criminal activity”.

“So where are the contingency plans when our police forces find themselves unable to check the databases of 28 EU countries at the touch of a button? If only she would deign to tell us, then maybe we could judge.”

“Just last year, a not-so-distant era when Theresa May made perfectly rational arguments against leaving Europe, she warned that being in the UK makes us “more secure from crime and terrorism”,” Mr Clegg will add according to close sources.

At the weekend, The Independent revealed that data experts fear the Government is failing to recognize the danger to businesses and the fight against terrorism from losing information-sharing rights.

Eurorpol – Holds all the data?

On Monday, Ms May was asked if she had an “alternative plan” to keep the national security data flowing but simply referred vaguely to trying to agree “appropriate oversight” of the information.

Instead, the Prime Minister vowed: “I am very clear that the European Court of Justice and its jurisdiction in the UK is going to be ended”.

In a speech in London, Mr Clegg is also expected to criticise a “pact of silence” between Ms May and Jeremy Corbyn, neither of whom have properly explained their plans for Brexit.