Liam Norton was questioned over the group’s tactics on Wednesday morning, following days of sit-down protests which have caused chaos for thousands of motorists.
Reid landed some early blows in the debate ridiculing Mr Norton, who has reportedly not insulated his own home because it costs “tens of thousands” to carry out and millions of other people can’t afford it.
Reid said: “Is this the case? You’re saying you would risk your life for Insulate Britain but you not going insulate your own home? Sorry if it sounds patronising but it seems that completely sabotages your cause.”
The host asked him again if he was prepared to lose his life during the stunts to raise awareness about having UK’s homes insulated by 2030.
Mr Norton responded: “People are going to lose their lives if nothing is done.”
He was asked whether he was willing to risk the lives of one of his protesters if they were hit by a motorist. “It’s terrible isn’t it?” he said.
The interview became heated after the guest compared the movement to Winston Churchill’s stand against fascism and Adolf Hitler.
“Do you know how many MPs supported Churchill in 1937?”, Mr Norton asked the panel.
“I don’t care” Madeley replies with a screwed up face.
Norton continued: “Six MPs and Churchill was right wasn’t he but only six supported him.”
The GMB guest host, retorted: “You’re comparing yourself to Churchill? That is the most twisted parallel I think I have ever heard.”
But the Insulate Britain activist stuck to his guns, saying: “I’m putting myself in a historical situation where the public aren’t always with you but you are still right. And we’re right now. We’re talking about the destruction of our economy and the destruction of our health service.”
Mr Norton then angrily stormed off the set ranting about the “state of things” as Madeley laughed at him.
Panellist Dawn Neesom then made her own comparison by comparing Insulate Britain to terrorists.
The Transport Secretary said the injunction will come into effect later on Wednesday.
The government sought the move to stop environmental activists from shutting down the M25 after five days of protests causing massive tailbacks.
Writing for the Daily Mail alongside Transport Secretary Grant Shapps, Ms Patel said the Home Office is working with National Highways to take legal action against the Insulate Britain group in a bid to “ensure they cannot keep disrupting and endangering people’s lives”.