Mr Lansman called for Labour MPs to get behind a future transformative Government.
He said: “Am I the radical man? I think I’m the mainstream man, Momentum is the new mainstream.”
Speaking ahead of local elections where his group are expected to gain a significant foothold in Haringey Council, a first for Momentum, he then contradicted himself by claiming they were developing radical plans.
He continued: “I think we could be only months away from a Corbyn Government.
“I think we have got a much greater opportunity here for radical change.”
Despite insisting he was the “mainstream man” he repeatedly took the opportunity to call for radical change.
He added: “We are developing radical plans and I think a lot of local authorities are thinking of new ways of delivering public services in the public sector and that is what I want to see and I don’t think that is radical, I think its now mainstream.”
Asked if he would commit to ideas which have been suggested such as raising council tax on bigger houses or cutting wages he called for new houses to be built.
Mr Lansman said: “We have hardly built any houses in Britain for generations.”
When pressed on whether Momentum would campaign for the deselection of MPs who did not back Labour leader Jeremy Corbyn’s agenda he claimed they would not.
On elements within the Parliamentary Labour Party (PLP) holding Corbyn back from an election victory, he said he was “pleased by the new spirit of unity” in the party.
He said: “I am pleased with the new spirit of unity that we saw on the NEC this week, that I think we now see in the PLP that recognises that Jeremy is here to stay that we are seeking a transformative government at the next election.”
The interview comes after an aide to former Labour Prime Minister Tony Blair urged moderate Labour MPs to stand up and makes themselves heard as the party risks lurching further to the left under the leadership of Jeremy Corbyn.
Writing in The Times, Philip Collins has said Labour representatives should “take one step to the right” and break away from the increasingly Left-leaning leader.
He says: “Nobody has to put up with this. Labour MPs should now do what they have threatened many times in private and what they told The Times this week they would do.
“Labour MPs who know Mr Corbyn would be a shocking prime minister — and there are lots of them — should take one step to the right in the Commons, literally and figuratively, and create their own grouping. If there are enough of them they might even become the official opposition.
“They should do this at once, as a way of retrieving a reputation for principle, rather than doing so simply because they are frightened of deselection.
“The accusation against the right of the party is always that they act purely out of career self-interest. The way they are framing the argument seems to confirm that ungenerous description.”