Use of military force against Russia would violate international law

Use of military force against Russia by the UK would violate international law, according to one legal academic.

Following the nerve agent attack in Salisbury, Professor Michael Schmitt, of the University of Exeter explained that the use of force by the UK would not be authorised.

He said: “The Prime Minister has labelled the assassination attempts a ‘use of force’.

“Under international law, the use of force by one state against another is a violation of the UN Charter and customary international law unless it is done in self-defence or with Security Council authorisation.

“But the use of force by the UK in self-defence is not authorised; a military response by the UK would be precluded by the principle of ‘immediacy’, which does not allow a military response against an attack that is over.

“International law does not permit a victim state to simply retaliate against or punish another state.”

Professor Schmitt said Britain could take “countermeasures”, including closing territorial waters to Russian flagged vessels.

He added: “What has been done - expelling diplomats - is known as retorsion in international law.

“This term refers to an action that is ‘unfriendly’ but is not unlawful and therefore does not require an unlawful act by another country to justify it.”