Jeremy Corbyn has told rebel MPs to “think on and think again” over a “bizarre” plan to sue for the name of the Labour party if he is reelected and a breakaway group of MPs attempt to form a rival parliamentary bloc.

The Labour leader responded to reports that some dissenting MPs were preparing to elect their own leader and launch a legal battle for the party’s name and assets if Owen Smith loses the leadership contest.

Speaking at a campaign event in Leeds on Saturday, Corbyn said: “We are getting into some fairly bizarre territory here, where unnamed MPs, funded from unnamed sources, are apparently trying to challenge – via the Daily Telegraph, very interesting – the very existence of this party.

“I say to them: ‘Think on and think again.’ This party was founded by brave people, pioneers who achieved a great deal, and this party has a huge membership and, under the Registration of Parties Act, we are the Labour party.

“There’s no alternative, there’s no other party. We are the Labour party, and I’m very proud to be the leader of the Labour party.”

Corbyn denied his leadership could trigger a split. “Sorry, this is nonsense, whoever is saying my leadership is leading to a breakup of the party?” he asked. “Since I became leader, membership has doubled, activity has increased.”

Corbyn’s remarks followed the shadow chancellor’s call for Smith to condemn any attempts to split the party.

John McDonnell said: “The democratic process is fundamental to Labour party values and all candidates must commit to respecting the outcome of this election. We call on Owen Smith to condemn the minority of MPs supporting his campaign who are threatening to subvert the outcome of this election and cause enormous damage to the Labour party.”



Owen Smith speaks at a rally at the Headingley stadium in Leeds. Photograph: Andrew Yates/Reuters

Responding to the intervention, Smith said he would “not indulge in gossip”.

“This leadership process is now entirely about Labour members and supporters. We have a “one member, one vote” system, so MPs will have the same amount of say as all Labour members – exactly as it should be,” he said.

On Saturday, Smith took his battle to topple Corbyn into “enemy territory” with a campaign push in Liverpool, seen as a Corbyn stronghold. Corbyn was due to hold rallies in Hull and Leeds.

The former shadow cabinet member Angela Eagle warned Labour MPs to moderate their language after Smith was forced to apologise for controversial comments aimed at Theresa May.

Smith, who won more support from MPs to become the “unity” candidate against Corbyn, was widely criticised for saying he wanted to “smash” the prime minister “back on her heels”.

Eagle said: “He should have, and has, apologised. As someone that has heard cruel words spoken about me, I know that language matters. And we’ve all got a responsibility to be sensitive with our use of language.

“Owen has shown a capacity to recognise, and apologise for, insensitivity, and that’s important.”

Eagle said it was “extraordinarily disingenuous” for Corbyn’s team to “cloak Jeremy in the mantle of feminism by saying that we have to be sensitive about our use of language, especially around women MPs”.

Angela Eagle withdrew from the leadership race after more MPs and MEPs voted for Smith. Photograph: Jack Taylor/Getty Images

The former shadow business secretary insisted she was not taking it personally that more anti-Corbyn MPs had backed Smith over her, and that she was trying not to dwell on threats received since she became the first leadership challenger.

“I don’t want to dwell on it, partially because if I dwell on it too much, or I talk about it too much, I just get a load more,” she said.

Smith initially refused to apologise for his comments regarding May but was forced to do so after the controversy mounted.

During his visit to Liverpool he will attend the city’s gay pride celebrations and meet party members at a special event.