The cost of insuring Ukraine’s debt against restructuring or default rose to its highest since the 2004 Orange Revolution on Tuesday, as investors fretted that the Kremlin’s spat with the west could spill over into a vast country of 46m people that straddles the divide between a resurgent Russia and the European Union.

Worries about the debt have intensified after a dispute over the use by Russian warships of the Ukrainian Black Sea port of Sevastopol.