Northern Ireland protocol: what is the ‘doctrine of necessity’?

Liz Truss published a bill designed to hand the government powers to neutralise parts of the protocol on customs rules, state aid and the jurisdiction of the European court of justice. Photograph: Niall Carson/PA

In justifying its attempt to unilaterally overturn parts of the post-Brexit agreement with the EU, the UK government has invoked a little-known legal principle known as the “doctrine of necessity”. The loophole is allowed by the UN’s International Law Commission to be used by a state facing “grave and imminent peril”.

But the government’s ex-legal adviser Jonathan Jones said the EU would find the use of the doctrine “completely unpersuasive”.