Reform UK London Assembly members walked out of a City Hall meeting in a clash over Havering leaving the capital.
Keith Prince and Alex Wilson, the two Reform members on the assembly, quit a plenary session of the assembly as it descended into chaos on Thursday afternoon.
They blamed a decision by the chair Andrew Boff, a Conservative, who they accused of admitting a Liberal Democrat motion which they said falsely claimed that Cllr Prince, Leader of Havering Council, had rejected the principle of a referendum on Havering gaining independence from London.
Cllr Prince insisted he had never ruled out holding such a referendum, and that he had asserted many times that he is open to the possibility of it should there be enough public demand.
He said: “This motion is a shameless, unveiled attempt to sow disagreement between myself and my party colleagues where it doesn’t exist.
“By walking out of the Assembly today, we have made it abundantly clear that Reform UK will not stand for political gameplaying.”
He argued: “This flagrantly misleading motion should have never been admitted by the chair.“
But Susan Hall, leader of the Tories on the assembly, said: "I'm disappointed that Reform chose to leave the debate rather than stay behind to defend their comments, represent their constituents, and engage in the process.
“If they believed they'd been misrepresented, then the floor would have been theirs to make a stand.
“Instead what we have seen is Havering voters misled at the election and now abandoned on the floor of the Assembly, because Reform can't make their mind up."
Romford MP Andrew Rosindell, who defected to Reform from the Tories, previously raised the prospect that Havering could splinter away from London.
Ahead of the May local elections, Nigel Farage suggested other boroughs in east Outer London, could also quit the capital, including Bromley and Bexley.
After his party won control of Havering, the Reform leader said: “Many (local people) feel that their association is with Essex and ever since 1965 have slightly resented being part of Greater London.”
But during a council meeting later in May, Cllr Prince, a former leader of Redbridge council and ex-Tory, made clear he would not prioritise pursuing moves for a Havering independence vote.
He said: “I was born in (a part of) the county Essex which later became Havering. I can understand people’s attachment to our historic county identity.
“However, let me make this crystal clear. At this moment in time, from the research that I have done, it is quite clear that many of our residents would be significantly worse off financially if we were to leave London.”
He explained further: “So, while there are those who are emotionally attached to the attraction of leaving London, I and this administration have yet to be presented with a well-thought research and costed proposal which outlines the benefits to our residents.
“Therefore, we will not be wasting our time pursuing ‘Hexit’ or leaving the Greater London Authority, but we will be concentrated our time and energies on getting Havering back on track.”
Cllr Prince is under intense pressure to deliver major positive changes in Havering which is one of Reform’s flagship councils.
It has already been hit by one controversy after it emerged that the Mayor’s consort, Starbuck Coleman, had previously been dismissed from a job as a police officer after failing a drugs test.
