Lewes mayor and independent councillor Ruth O’Keeffe was named the linchpin in the vote for Lewes District Council leader by MP Norman Baker.
In a press release and a tweet, the Lewes MP called on the mayor to announce her support for Lib Dem candidate Sarah Osborne.
But Ruth said, with 20 Conservative, 18 Lib Dem and two UKIP members making up the councillors the bigger question was how the UKIP councillors would vote.
Donna Edmunds, UKIP councillor for Barcombe and Hamsey, said her group had not pledged support for either the Tories or the Lib Dems, despite the MP suggesting the two councillors would be voting for his party’s candidate.
Next week cllr James Page stands down as council leader and a vote will be called for his replacement.
A leader for the Tories has yet to be chosen.
Mr Baker said: “Independent councillor Ruth O’Keeffe will have the deciding vote on the future of Lewes District Council following a meeting last night (Monday) in which local Lib Dems voted to make Sarah Osborne, councillor for Plumpton, Streat, East Chiltington & St John Without, the new leader of the Lib Dem group on the council.
“This follows the recent sacking of cllr Rob Blackman as Deputy Leader of the Council and his removal from his cabinet position.
“Insiders calculate the vote will be a 20-20 split with Ruth having the deciding vote on whether to keep the Tories in power.
“Ruth O’Keeffe must know that her vote will decide whether Lewes has a Tory or Lib Dem District Council.
“Ruth and other district councillors have to announce whether they will support the Lib Dems who are fighting to increase the availability of social housing and improve the flood defences in the area.
“As an independent councillor Ruth O’Keeffe cannot sit on the fence for this one. People in Lewes have a right to know how she will vote next Wednesday.
“Having a new leader for the Lib Dem group offers an opportunity to renew the fight against the worst of the Tory policies. With cross party agreement the most unpopular decisions can be blocked, that is why I am calling on the remaining councillors to make their positions clear.”
Cllr O’Keeffe said: “Lewes District Council has 41 members. There are 20 Conservatives, 18 Liberal Democrats, two UKIP members and myself, an elected Independent.
“Whilst it is interesting to be singled out as the councillor who will decide the leadership election this seems to ignore the maths.
“I would think it is a bigger question as to which way the UKIP members would vote, and I am surprised that Norman Baker appears to assume they will vote with the Liberal Democrats.
“I shall, as always, be voting on the basis of all the information available to me on the day, with the other 40 members of the District Council, and again as always I will not be bullied by some strange campaign into making public declarations ahead of the event.
“I am however, interested by the importance that I am being accorded by the local MP which just goes to show that he is now convinced an Independent can make a difference.”