Two convicted killers and another long-term prisoner yesterday began a legal battle to overturn the blanket ban on jailed criminals voting in an issue of "fundamental constitutional importance" in next year's Scottish independence referendum.

The men claim a decision to exclude them is incompatible with their rights under the European Convention on Human Rights (ECHR) and is unlawful.

Murderers Andrew Gillon and Leslie Moohan and the third inmate Gary Gibson maintain that they want to vote in the poll on Scotland's future on September 18.

They have launched a judicial review at the Court of Session in Edinburgh to have sections of franchise legislation for the referendum which deny them and other inmates serving prison sentences the vote set aside.

Prisoners on remand will be entitled to vote in the poll on the country's future.

Scotland's senior law officer, the Lord Advocate Frank Mulholland QC, is opposing the judicial review petitions brought by the prisoners and maintains that the claims are misconceived and they are not entitled to the legal remedies sought.

The hearing continues.