How much does Britain need Russian gas - and what form could economic sanctions take?
The outrage over the apparent Russia state-backed assassination attempt on former double agent Sergei Skripal has seen the UK expel a number of diplomats.
Moscow has indicated it will return fire by banning a number of British officials in the near future.
But as inquiries continue over the use of a nerve agent in Salisbury, Wiltshire that left Skripal, 66, and his daughter Yulia, 33, fighting for their lives, could a damaging economic “war” be about to break out?
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There is speculation that if Theresa May and the British government does not get the answers it wants from Russian president Vladimir Putin then No.10 will be left with no alternative than to impose economic sanctions.
What form could these sanctions take?
Labour leader Jeremy Corbyn was this week roundly attacked by Tory MPs and some within his own party for raising the point that London-based Russian oligarchs are big donors to the Conservative party.
“We’re all familiar with the way huge fortunes, often acquired in the most dubious circumstances in Russia, sometimes connected with criminal elements, have ended up sheltering in London and trying to buy political influence in British party politics,” he said in the Commons.
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But the point remains that there is a lot of money in the UK held by a few well-known, well-connected individuals – think Roman Abramovich, owner of Premier League Chelsea FC.
Freezing their assets would send a strong message to Moscow – but with Brexit a year away, would Downing Street want to risk alienating Russian investors this way?
What about property?
Again, many Russian oligarchs have tens of millions tied up in UK property. The leaked Panama Papers of 2016 lifted the lid on the huge amounts of foreign money that was connected to property.
More than £170bn of UK property is now held overseas, much of it in London.
The Criminal Finance Act could be used to examine how the money used to buy premium London property was acquired.
But as with freezing assets, putting pressure on property buyers is likely to squeeze as many legitimate investors as expose rogue or criminal enterprises.
No.10 could also expand the use of Unexplained Wealth Orders, an investigative tool to help law enforcement act on corrupt assets.
A cold wind is blowing:
The Beast for the East exposed Britain’s fragile energy reserves. Some 80% of the UK’s 25 million homes are powered by gas – and around a quarter of the country’s electricity is generated by gas-fired power stations.
During the recent heavy snowfalls and period of plunging temperatures, the National Grid warned the country was running out of gas.
MORE: UK seeking other gas suppliers as part of Russian sanctions, says PM May
Russian supplier Gazprom claims it sold just over 16 billion cubic metres of gas to the UK last year – around 20% of the country’s total demand.
That figure is disputed by the Department for Business, Energy and Industrial Strategy, which says less than 1% comes from Russia.
However much gas Russia supplies directly to the UK, 35% of the gas the EU needs comes from Russia – so imposing some form of economic sanctions on Russia, which would doubtless respond in kind, could hurt everyone.
And, while we are still a member of the EU but with Brexit looming, the question is what appetite would the bloc have to support the UK in such a move?
Mrs May told MPs on Wednesday the UK was looking to alternatives to Russian supplies: “When we are looking to our gas supplies, we are indeed looking to other countries.
“We will be continuing to discuss with the European Union not just our energy security but that wider energy security issue.”
The situation is further complicated by the fact that Britain’s own oil giant BP has a 20% stake in Rosneft, the Russian oil and gas giant.
BP’s chief executive Bob Dudley sits on a board that is chaired by close Putin-associate Igor Sechin.