A leading figure in the Labour Party’s youth wing was arrested for assaulting his girlfriend in an apparent late night row on a high street, the Standard can reveal.

London Young Labour chairman Dan Young accepted a police caution after the incident involving his 19-year-old girlfriend.

Young, a councillor in Barking and Dagenham, was suspended from his role in Young Labour after being quizzed by police in east London.

Up to six activists then dramatically quit London Young Labour’s committee after the 24-year-old was subsequently reinstated as chair days later, sources said.

Members were then warned by party figures not to mention the incident online.

In an email to the committee, seen by the Standard, London Regional Director Alan Olive wrote: “I am aware that there may be messages posted on social media regarding Dan Young’s recent suspension. I need to remind everyone that posting comments about internal discipline matters is itself a matter that could lead the author(s) becoming subject to a separate discipline investigation.

“This could also apply to members who re-distribute, retweet or otherwise widen the original circulation.”

Young had been suspended from his position in Young Labour after the incident in Romford on Halloween after accepting the caution. He did not respond to questions from the Standard on the alleged assault or why he accepted the caution.

Around a week after the incident he posted a message on Facebook saying: “Today has put a lot of things into perspective. Don’t waste time on things that aren’t imperative to your happiness.”

Last week, Young was allegedly seen wearing a white ribbon in council offices in an apparent gesture of solidarity with a national campaign against domestic violence.

Darren Rodwell, the Labour leader of Barking and Dagenham council, said: “I can confirm that a serving councillor accepted a caution from the police, although I am not furnished with the full details of the incident as it is being investigated as we speak. Hopefully we will have a better understanding of the issue once this is concluded.”

The position of London Young Labour chair has previously been held by future Assembly Members, and is seen as an influential role for aspiring politicians.

A Labour spokesman said Young would be stepping down from the position when his term ends in two weeks.

“Dan Young has been warned about his future conduct and the responsibilities that come with being an elected representative of the Labour Party,” he said.

“He will be stepping down as chair of London Young Labour in the next two weeks when a new chair is elected.”

The Women’s Aid charity said police issuing cautions for domestic violence suggests it is being treated as a “not very serious” crime.

Polly Neate, the charity’s chief executive, said: “We also think that it’s vital that elected representatives, whether councillors or MPs, are held accountable.”

A Barking and Dagenham spokesman said the council had not received a complaint about the incident and would not be investigating unless a complaint is made. “It is a party matter,” he added.

A Scotland Yard spokesman said: “Police in Havering were called at 3am on Friday, 31 October to Romford to reports of a domestic assault.

“A 24-year-old man was arrested at the scene for common assault against a 19-year-old woman. He was taken to an east London police station. Neither person required medical attention.

“A 24-year-old man was later issued with a police caution for common assault.”