Former Militant leader Derek Hatton attended Labour's annual conference in Liverpool and says he exchanged a few "very pleasant, very welcoming" words with Jeremy Corbyn.
The former deputy leader of Liverpool City Council, who was expelled from the party in 1986 because of his membership of the Trotskyist group, praised Mr Corbyn's "charisma" and welcomed the tone of debate at the conference.
He told BBC Radio 4's PM programme that he might seek readmission to the party, but insisted: "I'm certainly not on my way back at all." Mr Hatton said: "I certainly think there's a big, big difference in the hall.
"People cheer at what I would say are all the right times. I definitely feel that there is an enthusiasm there hasn't been for a long time.
"I bumped into Jeremy this afternoon. It was the first time I've seen him in 30 years. He has developed a charisma that wasn't there 30 years ago."
Asked how his conversation with the Labour leader had gone, Mr Hatton said: "Very pleasant, very welcoming. All he said was 'Hello, nice to see you'."
Mr Hatton caused national controversy in the 1980s by setting an illegal budget and was denounced at the 1985 conference by then leader Neil Kinnock for sending redundancy notices by taxi to council workers. He told PM that some of the attitudes of the Thatcher era were resurfacing within the Labour Party.
"I certainly think some of the views and principles that were around in the 1980s are beginning to emerge again, which is a positive thing," he said.
"Whereas in the 1980s, it was led by the cities and the trade unions, here it is being led by the leader himself, which is causing confusion and dismay among the media and the right-wing MPs. They don't know what to do next."
On the issue of deselections, Mr Hatton said that "accountability to the party" was needed from MPs, who had a "duty" to represent the views of their constituency parties.