A trade union and a Labour MP have called for an investigation into the election of the party's top youth representative after the process was marred by claims of smears and bullying.
Jasmin Beckett was picked to join the powerful national executive committee (NEC) at a weekend conference in Scarborough, edging out James Elliott by the narrowest of margins in what was seen as a victory for moderates.
Mr Elliott, who wrote Jeremy Corbyn's youth manifesto as an adviser to his successful bid for the party leadership, was backed by the Unite union and the left-wing Momentum group.
MPs raised concerns after one activist complained that he had been pressured by a Unite representative to show her his completed ballot paper to prove that he had backed Mr Elliott.
Student Zac Harvey posted on Twitter a copy of a mobile phone message exchange as evidence.
There were also claims that Mr Elliott was the victim of a smear campaign related to allegations - already being investigated by Labour Students - of anti-Semitism in the Oxford University Labour Club.
And his supporters criticised the failure to accept demands for a recount after the rivals were separated by a margin of less than 0.2% of the total vote, which some said amounted to a single ballot paper.
Responding to the allegations of pressure on delegates, MP Tom Blenkinsop said: " Young Labour must be suspended and the events of today thoroughly investigated."
He was among a number of MPs to raise concerns.
A Unite spokesman insisted its representative had " acted with propriety at all times" in dealing with Mr Harvey and that allegations were " deliberately misleading and malicious, intended for no other reason than to bring this union into disrepute".
"The Labour party is due to examine the Young Labour elections including some concerning allegations of a smear campaign organised by one candidate against a rival," a spokesman said.
"Unite urges that a full and independent look at these elections is agreed, and we will happily cooperate fully in this process."
Labour offered no comment.