The Government is considering a wide range of sanctions against Russia, including Magnitsky measures targeted at individual human rights violators, if it does not receive a credible response from the Kremlin over the Salisbury nerve agent attack, Housing Minister Dominic Raab has signalled.

Mr Raab told BBC Radio 4's Today programme that an unsatisfactory response from Moscow "opens up the whole panoply of counter-measures from economic, financial, diplomatic measures, and there's, obviously, a lot of talk about the Magnitsky sanctions.

"Actually, the Government's brought forward asset freezing powers, which are new recently in recent legislation. There's also the visa bans element of it.

"I led the original debate back in 2012 calling for a Magnitsky law with David Miliband as a cross-party thing at the time, and I would be delighted to see us take the most robust approach. But, let's wait and see what the Russian government comes back and says."

Mr Raab downplayed the involvement of Nato in any response to Moscow, saying that Prime Minister Theresa May "chose her words very carefully" in her Commons statement on the Salisbury incident.

He said: "The words 'unlawful use of force' are different and have a different meaning in international law from 'armed attack'."

Former foreign secretary David Miliband urged the PM to seek international support, telling BBC Radio 4's Today programme: "The biggest thing she has to do in the next two days is to rally her allies.

"It is very significant and very worrying, frankly, that the White House has not felt able to point the finger at Russia in the last seven or eight days.

"And, I think that rallying the European allies, and, if possible, significant strands of American opinion, is absolutely key."