Strasbourg payout ruling due on jail vote ban
The European Court of Human Rights (ECHR) is due to rule on whether prisoners who have been denied the vote should get compensation.
The case concerns 10 men serving sentences in Scottish prisons who claim their human rights were breached when they were not allowed to vote.
In 2004 the ECHR said that a blanket ban on prisoners voting was unlawful.
But successive UK governments have not complied with this ruling.
The claimants - some of whom are convicted sex offenders - argue that their human rights were breached after they were not allowed to take part in the 2009 European elections.
If the prisoners' claims succeed, the government will have to pay them compensation, and will also face the prospect of making pay-outs in hundreds of similar cases that are also before the court.
In 2004 the ECHR in Strasbourg ruled that a UK blanket ban on prisoners voting was unlawful after it received a claim from convicted killer John Hirst.
Seven years later, MPs voted to keep the ban on prisoner voting - excluding those on remand - despite the ECHR's repeated calls for the UK to comply with its original ruling.
Convicted prisoners in the UK are banned from voting on the basis that they have forfeited that right by breaking the law and going to jail.
Last December a cross-party committee of MPs concluded that prisoners serving a jail term of a year or less could be entitled to vote - but this was never made law.
BBC home affairs correspondent Danny Shaw said: "Strasbourg has grown increasingly frustrated at the failure of ministers - under both Labour and the coalition - to comply with the ruling."
Prime Minister David Cameron has previously said that inmates will not be given the right to vote under his government, and said that the idea made him feel "physically sick".
Last October convicted murderers Peter Chester and George McGeoch lost a bid at the Supreme Court to win prisoners the right to vote in light of the ECHR's original 2004 ruling.
Mr Cameron described that particular decision as "a great victory for common sense".