Video-sharing app TikTok will be blocked on “all parliamentary devices and the wider parliamentary network”, the UK government said on Thursday, citing the need for cyber security.
The decision comes a week after the UK announced a ban on the Chinese-owned app on government phones and on the day TikTok chief executive Shou Zi Chew is being quizzed in the US over fears the app poses a national security risk to millions of Americans.
The ByteDance-owned app, which has 150 million users in the US, could be banned in the States completely if its Chinese owners do not sell their stake in the company.
A bipartisan bill granting President Joe Biden's administration the authority to ban TikTok has received White House endorsement.
Mr Chew will try to convince Congress that the social media app has never shared American users' data with the Chinese government.
Back in Britain, the commissions of the House of Commons and House of Lords said on Thursday they would follow the move made by the UK government on all official devices, amid fears of sensitive data being accessed by China.
A spokesman for Parliament said TikTok “will be blocked from all parliamentary devices and the wider parliamentary network”.
“Cyber security is a top priority for Parliament, however, we do not comment on specific details of our cyber or physical security controls, policies or incidents,” the spokesman added.
The Scottish Government also followed suit on Thursday, banning the social media app from its mobile phones and other corporate devices following discussions with the government at Westminster.
Scotland's Deputy First Minister John Swinney said the ban would begin immediately.
"Devices managed by the Scottish Government are configured in line with best practice from the National Cyber Security Centre, which helps us to manage any risk associated with the use of third-party applications," he said.
Why is the US concerned about TikTok?
"Our decision to prohibit the use of TikTok follows engagement with the UK government on the potential tracking and privacy risks from certain social media apps.
"Currently there is limited use of TikTok within government and limited need for staff to use the app on work devices. This ban will be implemented immediately. It does not extend to personal devices used by staff or the general public."
Last week, Scottish parliamentary authorities "strongly advised" MSPs to remove TikTok from any of their devices, including personal phones.
The BBC this week urged staff to delete the app from any corporate devices unless they were using them for editorial or marketing reasons.
Guidance sent to staff at the broadcaster on Sunday, as first reported by Deadline, said: "We don't recommend installing TikTok on a BBC corporate device unless there is a justified business reason. If you do not need TikTok for business reasons, TikTok should be deleted."
The official BBC TikTok account, which has 4.4 million followers, is still active on the platform and has continued to post content.
Beijing's embassy in the UK hit out at the move to block the app after the decision by the government.
And further prohibiting of ministers from using TikTok is likely to anger Beijing amid increasing tensions with the West.