The shadow chancellor Ed Balls has said there was cross-party agreement about not giving the vote to inmates and the ruling by the European Court of Human Rights (ECHR) was the “wrong thing”.
“This is one of those times in politics where there is cross-party consensus,” he said.
“The court first said this in 2004, that prisoners should be able to vote, and Labour then said we disagree and we did not implement it.
“I am all in favour of prisoners having the right kind of support and being rehabilitated but voting is one of the things I think you give up if you go to prison.
“So we all agree that this is the wrong thing.”
Mr Balls was speaking after the ECHR gave Mr Cameron a deadline of six months to change the law in Britain on prisoners’ voting rights.
The court acknowledged that it was up to national authorities to decide exactly who can vote from jail - but denying the right to all inmates indiscriminately is illegal.
A London law firm acting for more than 550 prisoners challenging UK voting rights laws warned that further delays in changing domestic rules could leave the Government facing damages payouts.
Leigh Day & Co is handling applications relating to inmates’ inability to vote in the May 2010 general election.