"Two big sticking points remain - where exactly the proceeds of the sale will be held, and what legal guarantees government will be given about the money going to good causes," they said.

"Essentially, despite committing to all proceeds going to good causes in public, Abramovich seems unwilling to give the same legal commitments, which would have backed up his public statements of about a week ago, that in the deal neither he nor his affiliates could basically try and stake a claim to that unpaid debt between Fordstam and Camberley.

"A deal which would allow the cash to be diverted during the deal would be a breach of sanctions and is seen as a red line for ministers."