If Britain leaves the European Convention of Human Rights after Brexit, it will trigger a “guillotine clause” that will nullify any UK-EU security partnership to fight crime and terrorism, under plans suggested by Brussels.

The security agreement would also be cancelled if the European Commission or the European Court of Justice decided that UK data protection standards did not match EU standards, according to slides presented by the commission to EU 27 diplomats.

The slides are “without prejudice” to a final UK-EU agreement and have not yet been agreed by the EU-27 government but give a strong indication of how the commission, which handles the Brexit talks on behalf of the EU, is thinking.

The European Convention of Human Rights (ECHR) is a charter policed by the European Court of Human Rights, which is not an EU insitution but part of the older 47 member state Council of Europe in Strasbourg.

Theresa May was reportedly planning to argue for Britain to quit the ECHR in her 2020 manifesto before she called an early election last year but this move could tie her and future governments' hands.

When she was Home Secretary Mrs May clashed with the ECHR, which prohibits torture and slavery while guaranteeing the right to a free trial and protests. She accused the court of frustrating her plans to deport hate preacher Abu Qatada.