BREXIT will make it harder for the Kremlin spies accused of carrying out the Salisbury nerve agent attack to be brought to justice, the UK Government has been warned.

Normally, if foreign nationals are charged with a serious crime in England, the Crown Prosecution Service (CPS) applies to their government to extradite them so they can stand trial.

But Russia does not permit the extradition of its citizens meaning the UK has had to rely on issuing European Arrest Warrants in the hope the two suspects may travel into the European Union at which point they could be apprehended and sent to Britain.

However, amid the splits in the Cabinet over what type of relationship to have with the EU27 the UK has yet to get an agreement with the EU to continue to participate in this scheme when it leaves the bloc in March.

Alyn Smith, the SNP MEP, told the Sunday National: “I fully support the UK’s application for a European Arrest Warrant as the two men clearly have a case to answer.

“But I can’t help but notice that the UK is seeking to benefit from the co-operation and solidarity through the EU that other parts of the UK administration are so keen to leave.”

He added: “Unless there is a withdrawal agreement [with the EU] all co-operation stops.”

Theresa May stated last week that two Russians have been charged with carrying out the nerve agent attack on Sergei and Yulia Skripal in Salisbury.

The National:

The suspects have been named as Alexander Petrov and Ruslan Boshirov

British security services said the men travelled to the UK under the names Alexander Petrov and Ruslan Boshirov, but believe they are aliases and are appealing for help uncovering their true identities.

The suspects fled back to Moscow hours after allegedly putting Novichok on Skripal’s front door on March 4, possibly using the same “perfume bottle” that poisoned Dawn Sturgess and Charlie Rowley in June.

Police said the men were both using legitimate passports issued by the Russian government and have “travelled extensively” to the UK and other European nations in the past.

The Prime Minister told the House of Commons that intelligence investigators had identified the suspects as Russian spies from the GRU intelligence service, where Skripal served as a colonel before turning for MI6.

The Kremlin repeated denials of any involvement in the Salisbury or Amesbury poisonings following the Prime Minister’s announcement.

They have not so far been charged with offences in relation to the poisoning of Rowley and Sturgess, who died days after being exposed to Novichok on June 30.

A Home Office spokeswoman said: “The UK Government has been clear that until we have left the EU, the UK remains a full member, with all the rights and obligations that entails – including those under the European Arrest Warrant Framework Decision.

“The draft Withdrawal Agreement will allow the UK to continue to participate in existing EU Justice and Home Affairs Council tools and measures, including the European Arrest Warrant (EAW), during the implementation period which ends on December 31, 2020.”

The UK has proposed a new, legally binding agreement on internal security which protects mutually beneficial aspects of co-operation and ensures that both the UK and the EU can continue to tackle security threats.

However, the EU has not accepted the UK’s offer and negotiations are still ongoing.