Sir Keir Starmer's Wikipedia page has been edited to remove references to him being a "millionaire".
The Labour MP for Holborn and St Pancras is expected to launch a bid to succeed Jeremy Corbyn as Labour leader and is currently the bookmakers' favourite.
But Sir Keir - who this week insisted he came from working class roots - has already found himself at the centre of controversy after a reference to him being a "millionaire" was added and removed several times from his page.
The changes were made in the last two days from internet addresses traced to St Albans and north west London, it is reported.
The shadow Brexit secretary’s team has denied any involvement.
The phrase was first added to the online encyclopaedia in the early hours of Tuesday morning from an IP address traced to Cricklewood, according to the revision history page.
The passage read: '''Sir Keir Starmer''' (born 2 September 1962) is a millionaire and a senior British politician and barrister".
A flurry of edits then followed as the claim was removed three times in just two days.
One edit explained the reference's removal by saying it was "not sourced and something the man in question denies".
"If re-included needs to be sourced and show his rebuttal," it added.
It comes after Sir Keir, a former high-flying human rights barrister and Director of Public Prosecutions, on Wednesday denied suggestions that he is too middle-class to lead the party.
Labour is seeking to regain the trust of northern working class voters, after losing a series of seats to the Conservative Party in former Labour heartlands.
Speaking to BBC Radio 4's Today programme on Wednesday, he said: "Of course we need to listen to all of our voters and our representatives in the North of England, but the leader of the Labour Party has to be able to speak to and for everybody in England, everybody in Scotland, everybody in Wales, and everybody in Northern Ireland.
"And, as for the sort of middle-class thrust, as you know, my dad worked in a factory, he was a toolmaker, and my mum was a nurse, and she contracted a very rare disease early in her life that meant she was constantly in need of NHS care.
"So, actually, my background isn't what people think it is. I know what it's like. I actually never had been in any workplace other than a factory until I left home for university. I'd never been in an office.
"So the idea that somehow I personally don't know what it's like for people across the country in all sorts of different circumstances is just not borne out," he said.
Sir Keir Starmer also told Radio 4: "As a lawyer, that's the one thing that defines my career - a passion for fighting injustice.
"In this case now, the injustice of poverty and inequality, and I'm very passionate about that. That is what is driving me forward, it's what's driven me so far, and certainly will drive me into the future."
Sir Keir has not yet announced his bid but has said he is "seriously considering" running for leader.
He said: "I am seriously considering. Obviously a lot of people have come to me to ask me to put my name forward, but I want to talk to colleagues, and that's what I'm doing."
Emily Thornberry yesterday announced she was standing, while Lisa Nandy and Yvette Cooper have also said they are considering running for the job.
The Standard has contacted Sir Kier's team for comment.
