Yanukovych, a former convict, is likely to emerge as the winner in Sunday's final round of the bitter presidential election. ­Private surveys indicate that he is between three and six points ahead of his rival, Yulia Tymoshenko, the prime minister. Today's run-off vote follows a preliminary round last month in which Yanukovych had a 10.3% lead.

Victory would allow him to avenge a humiliating defeat in 2004, when his bungling attempts to fix the vote unwittingly provoked the Orange Revolution and propelled his pro-western opponent, Viktor Yushchenko, into power. Since then Yushchenko and Tymoshenko, once Orange allies, have irrevocably fallen out.

In contrast to the existential struggle of 2004, when Ukraine's future as a democratic state appeared at stake, many voters now appear disillusioned with the Orange Revolution and both candidates. A growing number are preparing to vote "against all" - a Soviet-era category allowing them to register a protest vote.

The election follows a brutal ­campaign, poisonous even by the mud-slinging standards of Ukraine's murky politics. Last week Yanukovych's Party of the Regions forced through an amendment in parliament to voting procedures - a move that prompted furious accusations of fraud from both candidates.