The government won't explain why police have decided there is no basis to reinvestigate any of the 14 suspicious deaths on British soil that have been linked by US intelligence agencies to the Russian state, as revealed by a BuzzFeed News investigation last year.

In a short letter to home affairs select committee chair Yvette Cooper, home secretary Sajid Javid said a review of the cases by the Metropolitan police, launched in the wake of the Salisbury Novichok attack, had been completed.

"The police have confirmed that there is no basis on which to re-open any of the investigations," stated Javid, who said the government would not offer any further public comment on the review.

The letter — dated Aug. 23 but published by the committee on Tuesday — revealed that both Cooper and the chair of parliament's intelligence and security committee, Dominic Grieve, received secret briefings from security minister Ben Wallace on the details of the review, as well as on the reasons for the government refusing to publicly explain the reasons for the decision.

The briefings were given on Privy Council terms, which means that they are confidential and can include secret intelligence.

The original BuzzFeed News investigation in March 2017 revealed that British intelligence agencies had been sitting on high-grade intelligence from their US counterparts that pointed to Russian state involvement in the 14 suspicious deaths on UK soil. Yet in all 14 cases, British police ruled out foul play.

US intelligence sources told BuzzFeed News that a highly classified report on Russian state assassinations compiled for Congress by the Office of the Director of National Intelligence in 2016 asserted with “high confidence” that Russian financier Alexander Perepilichnyy, who was found dead outside his Surrey home, was murdered in a plot sanctioned by president Vladmir Putin.

The UK government's decision not to reopen the cases drew criticism on Wednesday from MPs who demanded that ministers fully explain the reasons behind it.

Conservative MP and former cabinet minister John Whittingdale said: "BuzzFeed did an immense amount of work, produced a great deal of material and I think it needs a much more substantive response as to why the concerns raised are not being pursued than just five lines saying 'We’ve looked at it and we don’t think there’s any basis.'

"When BuzzFeed originally raised this, people said 'Well, the Russian government doesn’t charge around the world killing people it doesn’t like'. We’d had [Alexander] Litvinenko but that was a long time ago.

"But actually Salisbury has shown that it does and therefore we need to look much more closely when someone who has fallen out with the Russian government meets a rather sudden and unexpected death."

Another former cabinet minister, Labour MP Ben Bradshaw, told BuzzFeed News: “This decision strikes me as extraordinary given the tough language used by Theresa May in the Commons today on the Salisbury murders.

"To throw in the towel on these other mysterious Russia-related deaths on the day of the identification of the Salisbury suspects is particularly perverse. To do so without any proper explanation whatsoever is even odder.

“Unless there are very strong national security reasons why the government cannot explain this decision or give more details for it, then the public are owed much greater openness than this.”

Details of the decision emerged on the same day as the UK government named two Russian nationals in connection with the Salisbury nerve agent attack, saying they were likely to be officers from Russia's GRU military intelligence service.

It was the public outcry following the attack on Sergei and Yulia Skripal in Salisbury in March that prompted then-home secretary Amber Rudd to launched the review of the deaths highlighted by BuzzFeed News in March, saying she wanted to be satisfied that allegations of Russian involvement were no more than that.

After the Salisbury poisoning in March, Lord Ian Blair, the former commissioner of the Met, said he backed Cooper's call for an investigation into the 14 suspicious deaths.

Lord Blair was in charge of the Met in 2006 when former Russian spy Alexander Litvinenko was killed with radioactive poison. An inquiry 10 years later concluded that the murder was probably the work of Russian secret service agents acting on the orders of Vladimir Putin.

Rudd said in March: "In the weeks to come, I will want to satisfy myself that the allegations are nothing more than that. The police and MI5 agree and will assist in that endeavour."

In his letter to Cooper, Javid said: "Clearly, should any new information become available, then the relevant police force will continue to monitor this position and take additional action as necessary."

Whittingdale added: "Given the public interest in this, I would like to see the government set out in rather more detail why they’ve reached that conclusion.

"The BuzzFeed investigation did actually raise a number of pieces of evidence which do suggest that the deaths were not natural or certainly bear further investigation, and to have a response just saying 'Well, we’ve looked at it and there’s no basis' — I don’t think that answers the questions that were raised in the original article."

Cooper has so far declined to comment.