Earlier today, Jeremy Corbyn's campaign team issued a list of 13 Labour MPs, denouncing them for their "abuse" of the leader and his supporters. The briefing cited Jess Phillips telling Diane Abbott to "fuck off", Tristram Hunt describing Labour as "in the shit", Tom Watson referring to Momentum as "a rabble" and John Woodcock calling a Corbyn PMQs performance a "fucking disaster",

Ian Austin, Neil Coyle, Ben Bradshaw, Frank Field, Anna Turley, Jamie Reed, Karl Turner, Stephen Kinnock and Tom Blenkinsop were also named in the list. Ahead of tonight's Sky News debate between Corbyn and Owen Smith, a spokesman demanded that the challenger "condemn the abuse instigated by his high-profile supporters". He said: "Owen Smith's campaign has become increasingly negative, focusing on attacking Jeremy Corbyn rather than presenting a positive vision for the party and country.

"For the sake of party unity, Owen must explicitly condemn those who have threatened to split the party and tear it apart, as well as condemn the abuse instigated by his high-profile supporters. He must also make concrete commitments to doing his bit to foster party unity.

"Jeremy Corbyn has consistently spoken about his desire to unite Labour in order to take on the Tories, and committed to continuing to appoint broad-based shadow cabinets should he be re-elected as leader."

But the briefing has sparked divisions on Corbyn's own side. An ally of the Labour leader told me:

This has caused dismay and anger among Jeremy's supporters in Westminster. It is pound shop Malcolm Tucker stuff. On a day when Jeremy united the Labour benches over grammar schools this just gives the Tories an excuse to change the subject and point the disunity finger at Labour. It is the height of incompetence from the leadership campaign media operation.

Sources close to the Corbyn campaign said that the list was issued by a junior member of the team and was not intended for official use.

A spokesman for Tom Watson said: "Tom Watson has received an apology from James Mills on behalf of the junior press officer in Jeremy Corbyn's campaign team who released this list by mistake."

A Labour MP named on the list said: "With one breath Jeremy calls for unity and for the party to come together and with the next they publish this anonymous hit-list. I think members will be really dismayed.

"For the record, none of the MPs they're targeting has ever talked about splitting the party. That's just not true. The only person who has threatened to split the party is John McDonnell."

Update: At last night's debate, Corbyn did not repeat his campaign's explanation and defended the list. "There was information put out there, which is statements made by colleagues on the record and is all out there in the public domain," he said. Smith had denounced the briefing as a "deselection list".

"You talk about trying to unite the party, but I find that quite hard to reconcile with something your campaign did just this evening, which was to publish a list, a deselection list if you like, of MPs including the deputy leader of our party, Tom Watson, who your campaign think transgressed against you in criticising you. That isn’t unifying, that is deeply divisive."

Update 2: Former cabinet minister Ben Bradshaw, one of those named on the list, has written letters of complaint to Jeremy Corbyn and to the chief whip, general secretary and Parliamentary Labour Party chair. They appear in full below.

Dear Jeremy,



I understand your office has named me to journalists as being among Labour MPs who have abused you or your supporters.



This is an extremely serious allegation, which no one from your office had the courtesy to put to me first. I would be extremely grateful if you could outline to me exactly what form this abuse is supposed to have taken.



With very best wishes,

Ben

To the chief whip, general secretary and Parliamentary Labour Party chair.

I would like to make a formal complaint about a briefing by Jeremy’s office to journalists accusing me of abusing him or his supporters. This is an extremely serious allegation, which Jeremy’s office did not have the courtesy of putting to me first. It is not the behaviour one would expect from a leader of the Labour Party.



For your information, I have written to Jeremy in similar terms and asked him to substantiate the allegation.

With very best wishes,

Ben