The local authority’s ruling group’s previous slender majority of just one has now been wiped out with the resignation of Hexham East county councillor Cath Homer.
The news was confirmed in an email from council chief executive Daljit Lally to the leaders of the main political groups.
According to this, the former councillor’s resignation was confirmed on November 4, leaving her seat vacant.
A by-election to fill the seat is expected to be held in December.
The move means the majority won by the Conservatives at the latest round of local elections in May has been wiped out, but the Tories remain the largest single political group.
Formerly a member of the local authority’s ruling council, in August last year Homer became the third member of the panel to quit in as many weeks following a row over the suspension of the council’s chief executive.
In a resignation letter sent to the Northumberland Conservative group, Homer said it had been the “pride of [her] life” to represent Hexham, but claimed she had not been supported against “anonymous personal and malicious attacks”.
“As you’d expect in local politics, there have been achievements and disappointments, however the satisfaction I have gained in being able to help individuals and organisations and make what I believe has been a positive difference to Hexham has been wonderful,” she added.
“This has been a difficult and distressing time, but when this has such a profound effect on my family too it is time to call it a day.
“With a heavy heart I am therefore resigning from [the county council] with immediate effect.
“I wish to thank all of the residents of Hexham East for their support over the last eight years, many of whom have now become friends, and I wish the various organisations I have been directly involved with or have helped along the way, the very best in the future.”
In a statement, Glen Sanderson, the leader of the council, said: “I am very grateful to Cath for her excellent service to her residents in Hexham East and to the county council.”
According to the council’s opposition Labour group, the resignation showed more evidence of splits appearing between the ruling Conservatives, following on from a parting swipe by Corbridge councillor Nick Oliver, after he was removed as chairman of the council’s Communities and Place Overview and Scrutiny Committee.
Labour leader Scott Dickinson said: “This is a damaging blow, as well as councillor taking swipes at the leadership, it has demonstrated it is a very fractious group running the council.
“This changes the council from blue to grey, it is now no overall control, and the Conservatives have lost that feather in their caps which they have boasted about for so long.
“It demonstrates how weak the leadership is.”
A notice of vacancy for Homer’s former Hexham East seat has now been posted on Northumberland County Council’s website.
A by-election will be scheduled if two eligible names are put forward to contest the position, with polls to be held later, possibly in December.