Sir Keir Starmer has said he has “no plans” to join the Bluesky social media platform.
There has been a rising wave of popularity for the app – an alternative to Elon Musk’s X – in recent weeks.
Bluesky has at times been the most downloaded app on both the US and UK Apple Stores, with many social media users leaving X in the wake of the US election.
But the prime minister told reporters that “at the moment” there are no plans to establish official UK government accounts or a personal one in his name.
Some politicians have already set up Bluesky accounts including former Labour leader Jeremy Corbyn and treasury minister Darren Jones.
Speaking at the G20 summit in Brazil, Sir Keir said it is “important for a government” to be able to communicate with “as many people as possible”, adding “we’re obviously still using Twitter (X)”.
X does not share its total user numbers but it is understood to be measured in the hundreds of millions.
Bluesky was started by Twitter co-founder Jack Dorsey in 2019. The platform announced this week it had surpassed 19 million users.
Despite helping fund and start it, Mr Dorsey is no longer part of the team behind the social network.
The key difference between Bluesky and most other social media platforms is that it is decentralised, meaning it is operated on independent servers and not those owned by the company.
It describes itself as “social media as it should be” – a place where people can come together over shared interests “and have some fun again”.
Many new users have said their decision to join Bluesky was driven by Elon Musk, who heavily backed Donald Trump’s election campaign and intends to remain involved in the new administration.
Last week, the Guardian announced it will no longer post on X, saying the US election underlined its concerns that Musk had been able to use X to “shape political discourse”.
