A third Conservative councillor from the local authority caught up in a row over rough sleepers and the royal wedding of Prince Harry and Meghan Markle has quit the party group in protest.
Windsor and Maidenhead Council leader Simon Dudley prompted outrage when he suggested beggars should be cleared from the streets of Windsor before the couple tie the knot in May.
Mr Dudley is expected to face a no-confidence vote brought by the council's opposition group on January 29.
He survived an attempt within his own Conservative group to oust him this week, but since then a third Tory councillor has resigned.
Geoffrey Hill announced on Thursday that he would follow in the footsteps of Paul Brimacombe and Asghar Majeed, who quit immediately after the vote, with all three continuing as Independent Conservatives.
Mr Hill remains as chairman of the Maidenhead Conservative Association, of which Theresa May is a member.
Explaining why he felt it necessary to resign he said: "I cannot continue to lend my support to Cllr Dudley as Leader and I do not agree with the majority of my fellow Conservative Councillors on this subject."
He added that there "is now a clear divergence between what the Maidenhead Conservative Group has become under the leadership of Cllr Dudley and what I consider it should be".
The council leader's comments "brought a lot of negative press towards the royal borough" he said.
He added: "It is a sin to bring the royal family into politics. I think that was very wrong."
The Royal Borough of Windsor and Maidenhead is a Conservative-controlled council.
Controversy erupted when Mr Dudley said beggars could present the town in a "sadly unfavourable light" when the royal wedding takes place in the spring.
In a letter to police, he complained about "aggressive begging and intimidation", and "bags and detritus" on the streets.
A petition to stop rough sleepers being taken off the streets attracted tens of thousands of signatures, while comedian Russell Brand urged neighbouring Slough Council to donate an existing building to help the homeless in the Windsor area.
Mr Dudley later apologised for his comments and said he was not referring to genuine homeless people, and that he regretted referring to Harry and Ms Markle's wedding at the time.