A woman prisoner displays bruises which she says were caused by mistreatment by prison guards.

Allegations by ex-prime minister Yuliya Tymoshenko that she was physically mistreated by prison guards, followed by counter-claims by prison authorities that this never happened, have caused controversy in the rest of Europe.

In an intense cycle of debate, there are reports that some politicians from EU countries will not attend the Euro 2012 football finals in Ukraine in protest. Some heavyweight political journals have argued that EU political leaders should not attend.

This is a sensitive subject, with powerful arguments on each side. But the debate highlights a key question: why are EU Member States taking such a close interest in Ukraine? The answer has been set out many times before in this blog.

EU Member States are concerned that opposition leaders in Ukraine, including Ms Tymoshenko, have been tried and (in every case so far) jailed through a court process which appears both selective and politically influenced.

EU leaders feel so strongly that this marks a significant deterioration in Ukraine’s democratic record that they have made clear that they are unlikely to sign or ratify the EU-Ukraine Association Agreement until opposition leaders are free from prison and able to participate in political activity.

The linkage between signature of the Association Agreement and the imprisonment of opposition leaders is important. Both the EU and Ukraine want the Agreement signed because it is the best mechanism to help Ukraine to become more like an EU country, boosting wealth and trade and promoting integration.

Yet despite their eagerness to see the Association Agreement signed, all EU leaders agree that for that to happen, Ukraine has to demonstrate that it adheres to European values, including on democracy and human rights. The UK line on this was set out in full recently by Europe Minister David Lidington.

The UK hopes Ukraine will respond to the growing concerns from the rest of Europe about the state of democracy in Ukraine – not just for the sake of Euro 2012, but to ensure Ukraine can take the steps needed to continue their integration with, and ultimately to join, the EU.

I discussed these issues on Ukrainian Channel 5 on 14 May (in Ukrainian).

Leigh Turner has been the British Ambassador to Ukraine since June 2008. You can read all his blog entries at blogs.fco.gov.uk/roller/turnerenglish (in English) or blogs.fco.gov.uk/roller/turner/ (Ukrainian)