The fact is, Putin does not want the Russian-speaking regions to break away from Ukraine. He has always spoken in favour of a federalisation of the country which would guarantee the language and civil rights of Russians living there.

This in itself is enough to infuriate Kiev, which sees the demand as interference in its internal affairs or as the thin end of a wedge. But the suggestion itself is not unreasonable. And it could provide the kind of get-out clause that would prevent the current terrifying situation from careering out of control.

The west needs to put pressure on Putin – but it needs to be the right kind of pressure. If there’s one thing I took away from three years of working closely with Kremlin officials, it was that Putin detests being lectured by outsiders, and tends to react badly to all criticism. There is not a single instance of his bowing to criticism by doing what the west demanded. There are plenty of instances of his doing the opposite. So David Cameron was right this weekend to combine his threats of further sanctions with a recognition that “there must be protections for Russian-speaking minorities” in Ukraine.