The dispute is the latest sign that Theresa May is struggling to strike a post-Brexit security deal

France is blocking Britain’s attempt to remain part of a European Union security system that helps to identify foreign criminals and is designed to keep the public safe.

The government wants a guarantee that it can continue to access and share vital DNA, fingerprint and vehicle information with other European countries after Brexit.

Ministers have said that Britain’s participation in the so-called Prüm Convention is “clearly in the national interest”. The system allowed French and Belgian authorities to identify the terrorists responsible for the Paris attacks in November 2015.

Britain has been rebuffed, however, with France leading the resistance at a recent meeting to its efforts to join a “Prüm 2”. A senior government figure said: “Normally France is quite helpful when it comes