Some EU member states have announced that they will no longer extradite their nationals to the UK after Brexit.
The Home Office said 10 nations, including France, Germany and Poland, have notified the UK of their refusal to allow their nationals to be extradited.
Two others – Austria and the Czech Republic – will only hand over suspects to the UK with their consent.
The European Arrest Warrant, introduced in 2004, called on member states to arrest suspects and transfer them to countries where they were wanted by law enforcement agencies.
The letter, sent by the Home Office to the EU Committee of the House of Lords, was dated earlier this month and was first reported by The Times.
It says: “I can confirm that a total of 10 EU member states have announced their intention to exercise an absolute ban on the extradition of their own nationals. This includes Croatia, Finland, France, Germany, Greece, Latvia, Poland, Slovakia, Slovenia and Sweden.
“In addition, Austria and the Czech Republic have established that their own nationals are only extradited with their consent.
“If the member states refuse to extradite their nationals, the agreement obliges the state concerned to refer the case to its own law enforcement authorities. In such cases, the agreement provides for an obligation to provide adequate support to victims and witnesses. “