Prisoners are currently banned from voting

The estimated figure from William Smith's solicitors emerged in a parliamentary answer to the SNP from Justice Minister Cathy Jamieson.

Mr Smith persuaded the Court of Session that the ban on prisoners voting was contrary to human rights laws.

The SNP said taxpayers' money should be spent on victims of crime.

The final costs of the case have not yet been submitted.

Taxpayers don't expect their hard-earned cash to go towards a convicted drug dealer pursuing his whim and fancy Kenny McAskill SNP

The Court of Session's ruling could result in a legal challenge to the Holyrood elections and compensation claims from prisoners.

Smith, a convicted drug dealer, took legal action after he was barred from voting in the 2003 Scottish Parliament election.

The judges upheld a decision not to allow him to register while he was in Glenochil Prison, Clackmannanshire, serving a five-year sentence.

However, they also ruled that banning prisoners from voting breached the Convention on Human Rights and made a declaration of incompatibility.

SNP justice spokesman, Kenny MacAskill, told the BBC's Good Morning Scotland programme it was outrageous that legal aid funds were being spent on the case.

"Legally, there is a limited budget. It comes from taxpayers' hard-earned cash," he said.

"They expect it to go towards victims of domestic violence or those suffering accidents at work.

"They don't expect it to go towards a convicted drug dealer pursuing his whim and fancy.

"He put himself outside the law. He was punished and �5,000 would be better spent seeing justice for victims."