Boris Johnson claims it is 'overwhelmingly likely' Vladimir Putin personally ordered Salisbury spy attack

Boris Johnson has claimed it is “overwhelmingly likely” that Vladimir Putin personally ordered the Salisbury spy attack.

The Foreign Secretary’s decision to formally lay the blame for the nerve agent attack at the door of the Russian President came as the war of words between Moscow and the UK escalated.

Mr Johnson said: "Our quarrel is with Putin's Kremlin, and with his decision, and we think it overwhelmingly likely that it was his decision to direct the use of a nerve agent on the streets of the UK, on the streets of Europe, for the first time since the Second World War.

“That is why we are at odds with Russia."

The Kremlin moved immediately to reject Mr Johnson's claim and said it was "shocking and inexcusable".

Mr Putin's spokesman Dmitry Peskov said in a statement carried by Russian news agencies that the Foreign Secretary's statement represented a "breach of diplomatic propriety".

Mr Johnson’s accusation came after Sergei Lavrov, Russia’s foreign minister, accused Gavin Williamson, the Defence Secretary of being uneducated after he told Moscow on Thursday to “shut up”.

Mr Lavrov also confirmed that Moscow will expel UK diplomats in response to Theresa May’s decision to kick out 23 Russian officials.

It came as Jens Stoltenberg, Nato secretary general, warned Russia not to “underestimate the resolve and the unity” of the alliance.

He also reiterated Nato’s belief that there was “no reason” to doubt Britain’s assessment that Moscow was to blame for the poisoning of former double agent Sergei Skripal and his daughter.

Meanwhile, Jeremy Corbyn, the Labour leader, faced growing pressure from his own frontbench over his response to the incident as Sir Keir Starmer, the shadow Brexit secretary, gave Mrs May’s approach his unqualified support.

The British Government is anticipating a tit-for-tat response from Moscow after Mrs May outlined a series of retaliatory measures on Wednesday in response to the issue.

As well as expelling 23 diplomats, Mrs May also suspended all high-level contact with the Kremlin and set out plans to freeze Russian assets where such action is deemed necessary.

Mr Lavrov made clear that Russia will respond with its own measures when he was asked if Moscow would expel UK diplomats.

"Of course we will," he said.

Mr Lavrov also responded to the pointed remarks made by Mr Williamson when he claimed Russia should “go away” and “shut up”.

Mr Lavrov said of the Defence Secretary: “Maybe he is just not educated.”

The leaders of the US, France, Germany and the UK issued a joint statement on Thursday saying that there was “no plausible alternative explanation” to Russian responsibility for the attack.

Nato has also given the UK its full backing and Mr Stoltenberg insisted on Friday that the “United Kingdom is not alone, all allies stand in solidarity with the United Kingdom”.

Mr Stoltenberg also warned Moscow against questioning Nato’s commitment to upholding the international rule of law.

He told BBC Radio 4’s Today programme: “I am absolutely certain that Russia has underestimated the resolve and the unity of Nato allies when we have implemented different kinds of sanctions over the last years.

“The economic sanctions have been effective and they have come from all Nato allies and many other countries.

“Nato has implemented the biggest enforcement of collective defence since the end of the Cold War with deployment of battlegroups to the eastern part of the alliance all led by the UK in Estonia and we see now an increase in defence spending across Europe and Canada.”

He said the measures announced by Mrs May on Wednesday were part of wider action taken by Nato and that “it shows clearly that it has costs, it has consequences when Russia is behaving the way they are behaving”.

He added: “We have no reason to doubt the findings and the assessments made by the British Government not least because this takes place at the backdrop of a pattern of reckless behaviour by Russia over many years.”

Mr Stoltenberg said Nato was ready to cooperate with Russia “if they respect some basic norms and rules for international behaviour”.

The Nato chief’s unequivocal backing of the UK’s assessment of the nerve agent attack in Salisbury came as the rift between Mr Corbyn and many Labour MPs over the issue continued to grow.  

Mr Corbyn has so far failed to explicitly back the Prime Minister’s conclusion that Russia was culpable for the attack and sparked further fury on Thursday when he suggested “mafia-like groups” could have carried out the poisoning.

A number of Labour frontbenchers have put themselves at odds with Mr Corbyn’s response and Sir Keir was the latest to do so as he gave his full support to Mrs May’s approach and said the Prime Minister had drawn the “right conclusion”.

He told BBC One’s Question Time programme: "I think it is very important that we support the action the Prime Minister laid out on Wednesday as a response to this unprovoked attack.”

He added: "This is not the first time, it needs to be called out with no ifs and no buts and we need strong action as set out by the Prime Minister on Wednesday."

Salisbury spy attack timeline