Concerns have been expressed over what are perceived as insufficient safeguards in UK law to protect persons amenable to concurrent criminal jurisdiction. These were particularly forceful where an accused person had material links to the UK. The Crime and Courts Act 2013 inserted a forum bar into the Extradition Act 2003 in an attempt to address the concerns. The bar, defined in ss.19B and 83A of 2003 Act, entered into force October 14, 2013. The first appellate judgement relating to it has been published, Dibden v. France  EWHC 3074 (Admin). It provides an indication of how the bar will operate in practice.
ARNELL, P. 2014. Extradition, the forum bar and transnational drug trafficking. Criminal law and justice weekly [online], 178(42), pages 623-624. Available from: https://www.lexisnexis.com/uk/legal/