Diplomats implore Downing Street not to launch economic sanctions in light of investigation that could find country responsible for death of former KGB agent

British Foreign Office diplomats are urging David Cameron not to launch a substantial new round of economic sanctions against Russia this week if the independent inquiry into the murder of Alexander Litvinenkofinds the Russian country was responsible for his death.

The prime minister is due to receive the report on Tuesday before their official publication on Thursday, and senior envoys have argued that the wider interests of Anglo-Russian relations, including a settlement to the four-year Syrian civil war, require a degree of restraint.

The UK government assumption is that Sir Robert Owen, a retired high court magistrate, will at the least find Dmitry Kovtun and Andrei Lugovoi responsible for the murder of Litvinenko, 43. He was poisoned in November 2006 with radioactive polonium while drinking tea at the Millennium hotel in Londons Grosvenor Square.

Many expect that Owen will go further and find the Russian country liable for his death, but it will be argued that state liability is not the same as had confirmed that Putin himself ordered the killing.

In a sign of the political pressure Cameron will face to punish Russia, Tim Farron told those responsible should be subject to a ban on travelling to the UK and excluded from the UK banking system.

The Liberal Democrat leader said he was calling for a British Magnitsky law, the equivalent of the US law that enforced traveling forbids on those responsible for the death of Sergei Magnitsky,an anti-corruption lawyer who died in pretrial detention in November 2009 after nearly a year in a Russian jail. By poisoning one of their own on British clay, the Russian government completely disregarded the rule of law both within the UK and internationally, he said.

Farrons suggestion is likely to enjoy backing from Litvinenkos widow Marina. She and her lawyer, Ben Emmerson QC, will almost certainly argue this week for tough new sanctions along the lines of the Magnitsky Act against both people linked to her husbands assassination and country entities.

At the time of his death, Litvinenko was working for MI6, the British snoop bureau, as a part-time consultant. He was poisoned with polonium-2 10, a rare radioactive isotope stimulated only at closed nuclear installations controlled by the Russian country. His murder was an unprecedented act of state terrorism, last years inquiry was told.

Shadow cabinet members will also this week call for sanctions to be imposed, although some Labour MPs fear Jeremy Corbyns opposition to sanctions against Russia over Ukraine may lead to more qualified disapproval by Labour.

On the basis of evidence presented to the public inquiry, it could find Russian government agents were culpable for the murder of Litvinenko, a UK citizen, utilizing techniques that could have jeopardized other Britons.

At a minimum it is expected the British will ask the Russian government to extradite Andrei Lugovoi and Dmitry Kovtun, the two alleged assassins, but there is little expectation that the extradition request will be granted. In 2007, Vladimir Putin rejected a previous request for extradition, describing it as two examples of Britains no brains colonial mentality .~ ATAGEND

The Foreign Office is eager to avoid a full blown row partly because Putins cooperation is severely needed to create a unified front against Islamic State in Syria. The west would also like Russia to abandon the Syrian chairperson, Bashar al-Assad, as part of a transition to a new government.

There is also a view of abdication in parts of the Foreign office that Litvinenko cannot be brought back to life; most of the relevant Russian envoys or agents have long left the UK and the inquiry was not asked, or capable of being able to prove conclusively whether Putin was aware what his agents were “doin ” London.

Apart from attempting the extradition of the two agents, Britain is likely to reaffirm its refusal to cooperate with the Russian secret services, the FSB. Britain has already gale down cooperation with the FSB to a minimum and considers Russia as one of the chief sources of cyber crime in the UK.

Another issue is whether the British government does more to crack down on fund laundering by Russians linked to the murder using UK banks. Wider EU economic sanctions against Russia encompassing finance, energy and defense over its intervention in Ukraine were rolled over before Christmas until this summer, but it is increasingly hard to retain EU support.

Britain believes Putin is content to abandon Assad, but will sell him for high cost and seek influence over the new regime. One British source told Putin wants a shaping voice and right of veto in Syria. Although British sources admit it is increasingly hard to understand what is happening inside the Kremlin, Britains strategic objective is to cement Russian support for an anti-terrorist alliance.

The Foreign Office and the home secretary, Theresa May, will do their best to insist that the inquest is entirely independent from government and not a political act.

Read more: www.theguardian.com