Due to a very high number of Polish nationals residing in the United Kingdom (UK), almost half of the European Arrest Warrants (“EAW”) issued in Poland over recent years have been executed in the UK. One of the advantages of the EAW is the bypassing of rules preventing the extradition of a state’s own nationals. According to Polish law, in the case of extradition under an international agreement, the possibility of extraditing Polish nationals must be included in the agreement. One of many possible repercussions of Brexit – replacement of the EAW with a “traditional” extradition procedure – may result in substantial slowing down of the extradition and making the procedure much more expensive. This risk seems to be confirmed by some recent Polish cases discussed in this brief paper.