Gazprom uses gas to tighten noose on Ukraine

Ian Bond, from the CER said Mr Putin aims to reduce Ukraine to a "vassal state" by pushing for a loose federation in Ukraine under his control. He has upped the ante with a new strain of ethno-nationalism, laying a claim to all areas abroad deemed to be "historic Russia".

Mr Bond said US President Barack Obama and other Western leaders have made a "serious mistake" in categorically ruling out military action in Ukraine on the grounds that NATO’s guarantee does not cover non-members.

"In doing this, they have reassured Putin that the West’s reaction will be diplomatic and economic; knowing that so far the EU has been split on imposing tough sanctions, he may feel that the price of further intervention is worth paying.

"Western leaders should follow the Royal Navy motto: "Si vis pacem, para bellum" - If you want peace, prepare for war. They should state publicly that if Ukraine were attacked and called for assistance in exercising its right to self-defence, they would be ready to deploy NATO forces," he said.