With Moscow threatening to seize foreign business assets if the West imposes economic sanctions, how close are the UK's financial links to Russia?
Tory MP Brooks Newmark, a member of the Treasury Select Committee, suggested that the UK could target Russian business interests and bank accounts as a way to pile "a huge amount of pressure on Putin and his cronies".
So how much damage could the UK do if it tried to hit Russia in the wallet? According to figures from the Central Bank of Russia analysed by Sky News' Ed Conway, the UK has been one of the biggest sources of loans for Russian businesses over recent years.
Loans to Russian businesses sorted by country ($m)
This would be influenced by London's primacy as an international centre for finance, meaning that it would come from different countries but flow through the UK on its way to Moscow.
Of course, recent government papers snapped by photographers showed that the UK "should not support, for now, trade sanctions... or close London's financial centre to Russians".
The City of London would of course lose out on the extra custom if Russia was frozen out, but the graph shows how massive a blow the UK could inflict on Russia if they hit Putin with economic strictures.
As Conway points out, "they would have more impact if levied by the UK than by any other country in the world."