THERESA May is drawing up a “full spectrum” retaliation against Vladimir Putin for the nerve agent hit on spy Sergei Skripal, The Sun can reveal.

The PM has told ministers to prepare a powerful response across diplomatic, economic and military fronts to punish the Salisbury outrage - dubbed by Home Secretary Amber Rudd as “a brazen and reckless act”.

9 Theresa May told ministers to prepare for diplomatic, economic and military retaliation against Russia for the chemical weapons attack on British soil Credit: PA:Press Association

Intelligence chiefs are just “a few days” away from establishing hard proof that poison plot was ordered by Moscow.

Senior Whitehall sources said Mrs May accepts she must then initiate a response to match the public uproar that will meet the revelation that another state was behind a chemical weapons attack on British soil.

It will include:

The immediate expulsion of senior Russian diplomats and spies, as well as potentially cancelling Kremlin-linked oligarch’s visas to London, plus asset freezes and travel bans.

A statement of joint international condemnation from Britain’s closest allies - France’s President Emmanuel Macron and German leader Angela Merkel.

In the longer term, boosting Britain’s military deployments in Eastern Europe with more jets and troops, as well as a pushing for a NATO-wide reinforcement at the alliance’s summit in July.

9 Spooks are scrambling to work out the Kremlin masterplan behind the attempted murder Skripal and Yulia amid fears more mayhem is planned

What we know so far:

9 One senior minister said the UK has now entered a new Cold War with Russia Credit: Alamy Live News

Military scientists at Porton Down expect to be able to soon say beyond any doubt that the rare poison was devised in the SVR Russian foreign spy service’s notorious Yasenevo labs in Moscow.

One senior minister told The Sun: “We are in a new Cold War with Russia that is beginning to get hot.

“We need to completely overhaul our posture to reflect that.

“This is all about debilitating the West, so we have to reverse the psychology and make Putin look weak.”

The minister added: “Putin doesn’t dare attack the US, so he goes for us instead because of all the government’s current troubles. It is crucial we are seen to stand up to that”.

Spy bosses are also scrambling to work out the Kremlin masterplan behind the attempted murder of Colonel Skripal and daughter Yulia, The Sun has also been told, amid fears more mayhem is planned.

9 Home Secretary Amber Rudd dubbed the attempted assassination of Sergei Skripal 'a brazen and reckless act'

MI5 and MI6 were left startled by the audacity of the Russian president’s “wet job” order, which he knew would be swiftly traced back to Moscow because of the poison's complexity.

Under Russian law, foreign assassinations can only be authorised by the President himself.

A senior security source dubbed the nerve agent hit a “seriously balls in your face” move.

The source added: “Why have they done this? What is their next move?

“This is what we’re trying to work out now. Putin is without doubt a deluded individual, and that makes him dangerous.”

9 Ex-Russian spy Sergei Skripal and daughter Yulia remain in a critical condition in hospital following the nerve agent attack on Sunday

Activity across Whitehall was intense last night to prepare for the retaliation, with the MoD, the Treasury, the Foreign Office and Home Office all drawing up a series of options for No10.

Foreign Secretary Boris Johnson is preparing a major telephone lobbying operation for Britain’s European allies in a bid to sign up to a joint statement of condemnation, as well as potential action at the UN.

Diplomats along with MI5 are drawing up an extensive list of Russian figures to expel, from declared SVR intelligence officers to oligarchs who back Mr Putin.

The PM will take a final decision on how many to throw out once the full intelligence assessment is delivered to her – which could come as early as the weekend.

9 Foreign Secretary Boris Johnson will call on Britain's European allies to sign a joint statement of condemnation against Russia Credit: Alamy Live News

9 The UK will look towards its closest European allies Germany's Angela Merkel and France's Emmanuel Macron Credit: AFP or licensors

And defence chiefs are looking at deploying another squadron of Typhoon jets to Estonia, and an extra Army battalion to Poland or Romania to bolster defences against renewed Russian aggression.

Pressure was mounting on Mrs May last night for the toughest response possible.

Backbench Tory MP Sir Edward Leigh dubbed it “a brazen act of war” if Russia is behind the attack.

Furious senior Tories even called for Russia’s ambassador to be ejected and his embassy closed down.

Accusing Putin of “behaving like a rogue state”, former Foreign Secretary Sir Malcom Rifkind added: “It is becoming progressively more difficult to contemplate normal diplomatic relations with such a government”.

9 Cops searching the home of Skripal in Salisbury Credit: Getty Images - Getty

NHS workers in hazardous material protective suits after former Russian spy Sergei Skripal and his daughter were taken ill in Salisbury

Tory MP grandee Sir Nicolas Soames tweeted: “The West has been pretty pathetic in sticking up for Democracy in Moscow and weak on Russian interference in Ukraine, the Balkans and Syria #forgoodnesssakewakeupandgetagrip”.

The Home Secretary vowed to bring Colonel Skripal’s twisted attackers to justice, as she branded his poisoning “a most outrageous crime”.

Addressing MPs in an emergency Commons statement, Ms Rudd also revealed the Government’s outrage over the chemical weapons use, saying: “The use of a nerve agent on UK soil was a brazen and reckless act”.

Home Secretary Amber Rudd updates MPs in Commons on nerve agent attack on ex-Russian spy Sergei Skripal

9 Credit: TWITTER

Significantly, she also repeatedly refused to dampen down mounting speculation about Moscow’s involvement.

In a strong suggestion of the retaliation to come, Ms Rudd instead told MPs: “There will come a time for attribution, and further consequences will then follow”.

Other MPs called for wider action, with Tom Tugendhat saying that Putin used "murder as an instrument of state policy" as he urged for a co-ordinated boycott of the World Cup.

His call was backed by Labour's Chris Bryant, who suggested it would be "difficult" for England to take part if Russian state involvement in the attack was proven, according to The Daily Mail.

The PM called for the police to be given “the time and space to actually conduct their investigation”.

But Mrs May added: “We will do what is appropriate, we will do what is right, if it is proved to be the case that this is State sponsored”.

But Defence Secretary Gavin Williamson told ITV1’s Good Morning Britain that President Putin’s regime posed an “ever greater threat” to Britain and the UK must be not be “pushed around” by another nation.

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The Russian embassy in London tried again to pour cold water on the frenzied speculation.

It tweeted: “When Boris Berezovsky and Alexander Perepilichny died in Britain, there was a lot of speculation in the media, then all the conclusions were classified, and no data provided to Russia.

"Same happening now, with MI6 agent Sergei Skripal poisoning”.