James Page, Tory leader of Lewes District Council until last month, has left the Conservatives and joined the Lib Dems.
His defection sparked a furious reaction, the new Conservative leader of the council Rob Blackman describing it as a “complete betrayal”.
The council is now comprised of 19 Conservatives, 19 Lib Dems, two UKIP and one Independent.
Cllr Page (Telscombe) said: “I have become very disillusioned with the Conservative party, and impressed with the approach of the local Lib Dems.
“The Tory ideology of small state seems to have translated locally to small minds, small ideas and a blind obedience to doctrine and party message. By contrast, the Lib Dems have shown they are genuinely interested in helping people, improving the district and where appropriate transcending politics to that end.”
He continued: “While the Lib Dems have been open-minded and inclusive, the Tories have been tribal and dismissive of alternative ideas to a destructive degree.
“It is in the interests of local people that the district council returns to Lib Dem control who will, I know, if given the opportunity, work collaboratively for the good of the district, as demonstrated by the great cross-party work in Newhaven that has generated more than £22 million of grants and regeneration activity. I hope my decision to change parties will get us to get back on track and overcome the very recent tribal U-turn. I encourage other Conservatives with similar concerns and a true desire to put residents first to follow suit by crossing the floor.”
Sarah Osborne, Lib Dem leader on Lewes District Council, said: “I very much welcome James’s decision. I have always recognised that he wanted to do his best for the district, but it was obvious he was increasingly out of step with the Tory group. By contrast, the Lib Dems will welcome his enthusiasm and commitment.”
Lewes’s Lib Dem MP Norman Baker said: “I am delighted that James is joining us. He has always been an independent thinking person with a desire to do his best for the local area. He will be much more at home in the Lib Dems.”
But angry Cllr Blackman, who won the leadership election by a single vote in February, said: “It is regrettable that James Page has made this decision and I know that all the people that have worked closely with him see this move as a complete betrayal.”
He added: “It seems the Lib Dems will extend an olive branch to anyone because they are desperate to return to power and overturn some of the very important decisions such as Special Expenses that James, myself and the Conservative group have made.”
Cllr Rob Blackman said: “James Page’s decision to join the Liberal Democrats makes a complete mockery of so much of the progress the Conservative group has achieved in recent times, most of which was unthinkingly opposed by the Liberal Democrats.
“James has made a big play about his disillusionment with his previous colleagues in the Conservative party. The Conservative party is a broad church with many points of view. I know James is a centreist politician and the more he wanders from the centre the more out of step he will find himself with those colleagues. But if he thinks that he won’t find similar issues with Lib Dems he is being spectacularly naive.”