Legal professions across the UK have united to call for full public consultation on the government’s proposal to opt out of more than 130 EU criminal justice measures, including the European arrest warrant (EAW).

The call follows reports that the prime minister David Cameron indicated during a trade visit to Brazil last week that the government intends to exercise its opt-out powers before the end of the year. The Law Societies of England and Wales, Scotland, Northern Ireland as well as the Bar Council have warned that the decision will hamper the fight against cross-border crime and threaten law and order in the UK.

The government has until the end of May 2014 to notify the European Commission (pictured) of any decision to opt out of all of the police and criminal justice measures adopted under the 1992 Treaty of Maastricht.

Law Society of England and Wales president Lucy Scott-Moncrieff said that a decision to remove the UK from so many criminal justice ministers, most of which are procedural and promote practical co-operation between member states in fighting cross-border crime, could have far-reaching implications. She urged the government to engage with practitioners to seek their views in an open and transparent consultation process.

Bar chief Michael Todd QC said: ‘Those who advocate an opt out of EU criminal justice measures assume that it will remove the UK from the scope of EU criminal justice, and that it may save money.’ But he said the UK’s opt-out can relate only to measures established before the Treaty of Lisbon came into force in 2009, which would be a ‘recipe for confusion and greater costs’.

Todd warned: ‘The loss of these measures, including the EAW, would directly threaten law and order in the UK.’

He said that the practical considerations involved in the fight against cross-border crime would mean that the UK would almost certainly need to seek to opt back into them. Todd said that there is ‘more than enough time’ for a full public consultation to assess the impact of the changes properly and urged the government to do so.

Austin Lafferty, president of the Law Society of Scotland, said: ‘A wholesale opt-out could have very serious consequences in fighting cross-border crime from both a practical and cost perspective.’ He warned that even if the UK is able to opt back in to some measures, it would cause ‘confusion, complexity and cost’.

He said: ‘This important decision should not be seen as a totemic pro/anti-EU issue. It should be taken on its own merits, based on practical experience and objective information.’

Law Society of Northern Ireland president Imelda McMillan added: ‘Failure of government to consult publicly on this very important decision would be a serious oversight and would raise significant concerns in the legal profession – at home and across Europe.’