Britain could be trapped in endless negotiations with the European Union by Theresa May's Brexit deal, the British government's top legal adviser has warned. In the full written advice by the attorney general, which the government was forced to publish after lawmakers found it in contempt of parliament, ministers are warned that the "backstop" insurance policy relating to Northern Ireland could last "indefinitely" if relations with the EU break down. In the advice, Attorney General Geoffrey Cox warns that the Northern Ireland "backstop" could last "indefinitely until a superseding agreement took its place."