THERESA May must hit Putin’s regime “in the pocket” by targeting dirty Russian money being secretly funnelled through Scotland, MPs and campaigners demand today.

The call comes as police launched a murder inquiry into the death of another prominent critic of the Russian President and as a diplomatic war of words broke out between London and Moscow.

As Russians go to the polls tomorrow to elect their president – Vladimir Putin is expected to win easily – Downing Street awaits the Kremlin’s retaliation to the UK’s sanctions over Salisbury.

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At Westminster, the SNP’s Alison Thewliss said the chemical attack in Wiltshire had “drawn into focus Russian interference in UK life and politics” and that for some time now there had been evidence of illicit Russian money being laundered under cover of a tangled web of financial products.

“The Sanctions and Anti Money-Laundering Bill currently going through Parliament is an opportunity for the UK Government to crack down on the scourge of Russian money laundering via Scottish Limited Partnerships[SLPs] and similar structures in England,” declared the Glasgow MP.

Noting how the Prime Minister in her Commons statement earlier this week had mentioned the need to tackle dirty money, Ms Thewliss said: “She must now bring forward amendments to the bill to tackle this scandal.

“If the UK Government miss this chance, this sends out the message to Russia that they aren’t serious. We cannot afford to ignore Russian money laundering on our doorstep any longer. “It’s time to hit Putin and his cronies in the pocket.”

READ MORE: Detective no longer critical as probe continues after Salisbury attack

Jackie Baillie, Scottish Labour's Economy Spokeswoman, pointed out how there had been numerous warnings about SLPs but the Conservative Government had failed to take proper measures.

"It must immediately take action on them and close these tax loopholes to ensure that no one is using Scotland to avoid paying tax or hiding murky enterprises," insisted the MSP for Dumbarton.

Tory MP Luke Graham stressed how Mrs May was committed to toughening up the anti-money laundering legislation and welcomed the UK Government’s work with the police and the finance sector “on ways to improve the action we take against money-laundering”.

Meanwhile, Duncan Hames, Director of Policy at Transparency International UK, the anti-corruption body, called for “serious action” from the UK Government to rid the country of dirty money from overseas.

He said: “It is clear London has routinely been the choice destination for Russians with suspicious wealth to move and they have had little trouble doing so, taking advantage of lax regulation and offshore secrecy. To help combat this the UK needs to accelerate the much-delayed plans for a public register of the real owners of overseas companies owning UK property.”

Last night, Scotland Yard announced it had launched a murder inquiry into the death of Nikolay Glushkov, a prominent Putin critic, after a post mortem suggested the 68-year-old businessman had been strangled at his home in south London, where he had lived for the past two years.

READ MORE: Death of Putin critic Nikolay Glushkov probed as police treat case as murder

The police stressed that “at this stage” there was nothing to suggest any link to the attempted murders by chemical agent in Salisbury nor was there any evidence of poisoning but the Met revealed the inquiry was being led by the Counter-Terrorism Command "because of the associations Mr Glushkov is believed to have had".

The retired financial director was a close friend of Boris Berezovsky, another Putin critic, dubbed "Vladimir Putin's personal enemy No 1". He was found hanged in the bathroom of his Berkshire home in 2013. An inquest recorded an open verdict.

At the time, Mr Glushkov said he would "never believe" the 67-year-old Russian oligarch had taken his own life.

Mr Berezowsky was also a friend of former spy Alexander Litvinenko, who was murdered in 2006. He was poisoned by ingesting polonium, a radioactive element. A public inquiry concluded he had been murdered by the Russian state, probably under the direct orders of Mr Putin.

Earlier this week, Amber Rudd, the Home Secretary, announced that MI5 and the police would reinvestigate a string of deaths on UK soil following claims of Russian involvement.

Buzzfeed, the news website, has highlighted 14 suspicious deaths that have been linked to Russia by spy agencies.

As Mrs May and her colleagues awaited Moscow’s response to the UK sanctions, which include expelling 23 Russian diplomats, Boris Johnson turned up the rhetorical heat by claiming it was "overwhelmingly likely" that Mr Putin had personally ordered the use of a nerve agent in the attack on the former double agent Sergei Skripal and his daughter Yulia.

The Kremlin issued a scathing response, branding the Foreign Secretary’s remarks “shocking and unpardonable diplomatic misconduct".

Alexander Yakovenko, Russia's ambassador to London, claimed the UK Government was using the Salisbury poisoning case simply to divert attention from Brexit.

He said Britain had put its weight behind an "anti-Russian campaign" as it tried to establish a new place for itself within Western society after EU withdrawal.

In London, Mrs May received phonecalls from Malcolm Turbull, the Australian Prime Minister, Paolo Gentiloni, the Italian premier, and Donald Tusk, the European Council President, all affirming their “full support and solidarity” with Britain.

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In a separate development, Downing Street confirmed the PM had formally invited the Organisation for the Prohibition of Chemical Weapons to come to the UK to verify the Government’s analysis of the nerve agent used in the Salisbury attack.

A spokesman said: “Discussions are ongoing on the precise timing but we expect the process to begin imminently.”