Former deputy council leader Kanti Patel resigned from his post as High Barnet ward councillor on Tuesday, questioning the integrity of leader Brian Salinger and criticising his 'socialist housing policy'.
His action comes hot on the heels of the resignation of David Miller, who quit his post last week as chairman of the Chipping Barnet Conservative Association.
Mr Patel resigned as deputy leader in July, saying he could not agree with Mr Salinger's socialist housing policy', but vowing to remain as a councillor.
This changed on Tuesday, with Mr Patel saying: "There's no place for integrity in the party anymore. That's reflected by Mr Salinger's own record" an apparent reference to a local government ombudsman finding that Mr Salinger was guilty of maladministration before becoming leader.
Mr Patel also denied rumours of an acrimonious leaving. "I've nothing against Mr Salinger personally," he insisted.
Mr Patel also blamed Mr Salinger for the resignation of Mr Miller, saying the latter had been forced to go amid criticism from Mr Salinger and other senior Conservative members of his decision to ask for an independent inquiry into the sale of the freehold of Barnet FC's Underhill stadium in 2002.
Mr Miller confirmed this was part of the reason, but added: "Three-and-a-half years on the council has still not found a solution to Barnet FC's problems of getting a new stadium.
"I do think the council could have found a solution by now."
Mr Salinger said: "Kanti Patel supported our planning policies as a cabinet member.
"I'm always sorry when any member sees the need to resign."
A by-election will now be held.