Andy Burnham’s fingers must be aching. Between pitching to become the MP for Makerfield, continuing in his day job as the mayor of Greater Manchester and going for his regular runs, Keir Starmer’s would-be challenger has also found enough time to reply to dozens of posts on social media.

Since it became clear that Burnham planned to stand as a candidate in the Makerfield byelection last Thursday, allies have delighted in his snarky retorts on X, pointing to posts that combine humour with a passive-aggressive thumbs-up emoji as proof he is a natural, and refreshingly forthright, communicator.

When the Daily Mail ran a story claiming Burnham had staged a run, before driving home he pinged back that it was “part of my regular routine”. And when the broadcaster Andrew Neil accused him of pandering to “victimhood”, he replied: “You need to get out of London, Andrew.”

It is the kind of “combative progressivism” that Luke Charters, the Labour MP for York Outer, is delighted to see, arguing that his party has to understand the mechanics of social media algorithms if they don’t want their argument to be lost.

“If you can do that in a good-hearted, humorous way then you can cut through,” said Charters. “Farage has made a game of relatability for years, hiding behind pints and populism while his party couldn’t find a working men’s club with a satnav, but Andy doesn’t need to put on an act, whether that’s on the doorstep or on his feed. He just needs to live everyday life.”

He points to Burnham’s byelection campaign video, launched on Monday evening, which starts with a soundtrack of soaring strings from Elbow, continues with music from fellow Manchester bands James and Oasis, and concludes with an image of the Palace of Westminster. In the video Burnham says his attempt to win the Makerfield seat was motivated by the need to “change Labour” and describes the byelection as the “most consequential of our lives”.

Subtle it isn’t, but it does bear the hallmarks of a competent communicator, said the PR consultant Mark Borkowski. “He’s a natural,” said the media analyst. “He comes across as fearless and he looks comfortable in his own skin.”

Which is a marked contrast to the man whose job he wants to nab, he added. “[Keir] Starmer has struggled to project that same authenticity, and in the modern age you have to be a brilliant communicator as well as being good at your job.”

In the video, which shows Burnham sauntering along the streets of Makerfield and Manchester interacting with uniformly delighted members of the public, he appears to channel the style of his New York mayoral counterpart, Zohran Mamdani, said the Labour strategist John McTernan. “It’s like a love letter to Wigan and Manchester – he loves them and they love him back, and that’s precious in politics,” he said.

Burnham is also making the Labour party feel a bit better about itself after a bruising set of local election results, McTernan added. “Keir’s messaging seemed to be: ‘Well, things are shit, but don’t worry they are going to get shitter’, but progressive politics has to be about lift. His message recognises that.”

The Burnham communication strategy still shows signs of being rough around the edges; initially comments and retweets on his post on X appeared to be mistakenly blocked, which he told a supporter: “Yeh, took me a while to work that out!” And while his social media activity may be catnip to a subsection of the Labour faithful, his presence on TikTok, Instagram and YouTube is less hyperactive than on X, said the social media analyst Matt Navarra.

“Burnham is going to have to have a much more robust social strategy that leans into being entertaining as much as educating,” he said. “Content is king and he’ll need a team and support of creators across a range of platforms to get proper reach.”

While Burnham’s rootsy online persona was likely to be seen as trustworthy, it was also less algorithmically explosive than the “rage bait we see from the likes of Nigel Farage”, Navarra added. “Burnham beats Starmer for emotion, and [Wes] Streeting for authenticity, but Reform beats all three of them on understanding the raw attention-grabbing mechanics of social.”