As Britain expels 23 Russian diplomats, fears grow in Whitehall that row could escalate

The confrontation with Russia following the nerve agent attack in Salisbury may escalate, with Britain prepared to take further punitive measures if necessary.

Senior government sources say that plans are already in place for a further round of sanctions if Moscow continues with what they term as “brutal and aggressive actions”.

Security officials hold that the attempted murder of former Russian spy Sergei Skripal and his daughter Yulia was ordered at the “highest levels” of the Kremlin and the belligerent attitude taken by Vladimir Putin’s administration over the issue means that tensions are likely to continue rising.

Twenty-three Russian diplomats have been expelled by the UK. It is believed a “B list” is already in place details others to be thrown out if Moscow reacts in a “disproportionate” way to the measures announced by Theresa May in the Commons.

The British Prime Minister’s approach, the officials maintained, was “calibrated, calm and firm” and designed to highlight to the international community the gravity of what had occurred and the need for a “robust response”.

“Although we have announced this response, further options remain on the table. Economic, diplomatic, legislative and security capabilities can all be brought to bear if needed”, said a senior Government official. “If we don’t feel that what we have done thus far is having the required effect in the short, medium and long term – a change of behaviour from the Kremlin – we will look at them again and revise them.”

Investigations may be launched against individuals leading to possible charges of financial crimes and new legislation will be considered to counter espionage. There is no question of the UK launching cyber attacks on Russia, but existing measures to combat fake news and propaganda will be stepped up.

Mentioning Mr Putin by name, Ms May described the Salisbury attack as “ unlawful use of force by the Russian state against the UK.” Jeremy Corbyn faced criticism, including from some Labour MPs, for not endorsing this stance and suggesting that parties other than the Russian state could have been responsible for the act.

Mr Corbyn’s spokesman, Seumas Milne, later appeared to compare the intelligence assessment of the Salisbury attack to the false reports of Saddam Hussein’s weapons of mass destruction used to justify the invasion of Iraq by George W Bush and Tony Blair.

“I think obviously the Government has access to information and intelligence on this matter which others don’t” said Mr Milne. “However, also there’s a history in relation to WMD and intelligence which is problematic to put it mildly.”

It is understood, however, that as a privy councillor, Mr Corbyn was given a briefing on the intelligence in the Salisbury attack. A security source said that he was given the same information as received by the National Security Council on Tuesday morning before the Government made its decision on the measures to be taken.

But there was also demand for evidence from some of Britain’s Western allies. Ms May had claimed that the Government had their full backing and this was echoed by the Foreign Secretary with Boris Johnson tweeting: “International community standing in solidarity with UK against Russian aggression.”

The French government said it wanted firm proof of Russian involvement in the poisoning before it took action in solidarity with the UK. President Emmanuel Macron and French officials have declined to hold Moscow responsible so far; government spokesman Benjamin Griveaux said France was waiting for “definitive conclusions” and evidence that the “facts were completely true” before taking a position.

Matteo Salvini, who may become Italy’s next prime minister following the recent election responded to the alleged culpability of the Russian state with “we see and hear a lot of fake news” and that “in 2018 you don’t go around poisoning people”. However he added that if there were “concrete proof” of Moscow’s culpability then “we’d change our relationship” with Russia.