This leaves the Liberal Democrats with only 41 councillors, meaning a combination of Labour’s 39 and Greens’ 2 councillors could vote down Lib Dem motions and amendments.
Cllr Curran, who had been an advisor to Lib Dem deputy leader Cllr David Baker, said it had not been an easy decision, but that he felt he had “no alternative but to leave the Liberal Democrats and join Labour.”
He said: “I was bitterly disappointed with where the party was going nationally with Nick Clegg and I was also left disillusioned with the lack of resistance shown by the Lib Dems locally with all the savage cuts that have hit this city.
“The disgraceful decision to cancel the Forgemasters loan is a case in point. As Sheffield Lib Dem Councillors, we were asked to defend what turned out to be a completely unjustifiable decision and it soon transpired that all the reasons in favour of cancelling the loan were just a pack of lies.
“My personal values haven’t changed but the political landscape has. It is clear to me that Labour offers the only genuine progressive future for both Sheffield and Britain today.”
Paul Scriven, leader of Sheffield council said: “Clearly this has come as a real surprise to us as Ben hasn’t spoken to me or anyone else in the Group to let us know he was thinking of resigning, let alone defecting. He was only elected in May and just a couple of weeks ago he gave a speech in the Council chamber deriding Labour’s record.
“Obviously this is a personal decision for Ben, but it’s clear that the move has been orchestrated given that it is on the eve of our national conference in Liverpool. I find it hard to understand how he could have joined a party that has pledged to take money away from the area he represents, took us into an illegal war in Iraq and has bankrupted the entire country.”
Sheffield Labour Group’s new leader Julie Dore welcomed the defection. She said: “The doors are wide open for any other Lib Dems who feel uneasy with the Tory-led Coalition and who are sick to death of these spiteful cuts, which are being made too far, too fast and hitting the most vulnerable hardest.”
Paul Blomfield, Labour MP for Sheffield Central, which includes the Walkley Ward, said: “I know what a difficult decision this has been for Ben. Like many Lib Dem supporters in Sheffield he was deeply distressed by the way that the party has changed under Nick Clegg’s leadership, especially since joining the Tories in Government. I welcome him to Labour and I’m looking forward to working with him in Walkley ward in my constituency.”