The law was signed into law in April by US president Joe Biden after being proposed by the US congress and sets a deadline of 19^th January to agree its sale to a non-Chinese company or face a ban.

TikTok is owned by Chinese firm Bytedance and has faced accusations from some politicians about its links to the Chinese government, and avoided a previous attempt to ban the app during Donald Trump’s first presidency.

However, TikTok has repeatedly denied it is under Chinese government influence and has said it operates independently.

The social media platform, which has 170 million users in the US, has headquarters in Singapore and Los Angeles and says that its US user data is handled by US firm Oracle.

In its judgement on TikTok’s appeal against the ban, the US Court of Appeal decided to uphold the law, arguing that the divestment mandate in the law would survive an appeal under the first amendment of the US constitution, which broadly protects freedom of speech and press.

“Congress chose divestment as a means of paring away the PRC’s control – and thus containing the security threat – while maintaining the app and its algorithm for American users,” the ruling said.

“But if no qualifying divestment occurs – including because of the PRC’s or ByteDance’s unwillingness – many Americans may lose access to an outlet for expression, a source of community, and even a means of income.

“Congress judged it necessary to assume that risk given the grave national-security threats it perceived. And because the record reflects that congress’s decision was considered, consistent with longstanding regulatory practice, and devoid of an institutional aim to suppress particular messages or ideas, we are not in a position to set it aside.”

A TikTok spokesperson said:  “The Supreme Court has an established historical record of protecting Americans’ right to free speech, and we expect they will do just that on this important constitutional issue.

“Unfortunately, the TikTok ban was conceived and pushed through based upon inaccurate, flawed and hypothetical information, resulting in outright censorship of the American people. The TikTok ban, unless stopped, will silence the voices of over 170 million Americans here in the US and around the world on 19th January 2025.”