Ukraine is a country put together as recently as 1954, incorporating conquests from Poland and the Ottoman Empire. As the map shows, the Eastern Ukraine belonged to Russia before the rest of the country. Ukraine’s refusal to allow self-determination of its historically separate regions is incompatible with its aspiration to join the EU. Britain is encouraging this un-European behaviour by guaranteeing Ukraine’s territorial integrity through its mistaken triple treaty of 1994 (the Budapest Memorandum).
Britain made the same mistake in 1856 when it signed an earlier triple treaty, also designed to prevent Russian invasion, which failed to foresee the emergence of independence movements in the Ottoman Empire. That mistake led directly to the First World War.
Britain could now abrogate its badly-drafted treaty of 1994, which no longer serves any purpose as Britain and the US clearly do not intend to reunite Crimea with Ukraine by force. The US would be forced to admit the mistake and would follow suit. If the treaty had not existed Ukraine would have allowed Crimea to vote for independence. It would not have been necessary for Crimea to join the Russian Federation for protection against the US, Britain, and Kiev, a surrender of sovereignty which will remain a cause of dissension among the Tatar population. Britain should now admit to its 1994 mistake and bring self-determination and peace to the people of Ukraine.
(Note: the former Iron Curtain includes governments installed by the Red Army i.e. excluding Yugoslavia and Albania. This not relevant to the present dispute but was on the map for other purposes).
See The Crimean War (Tempus Publishing, 2007)