MI5 has warned Cambridge and other universities to stop working with China on key technologies or face prosecution for helping its spies.

In an unprecedented public espionage alert, the security service has called out 100 British academics taking funding from China's Ministry of State Security (MSS) for research on sensitive topics such as artificial intelligence (AI).

The stark warning reveals Beijing's spies have been secretly funding studies at British universities in key areas to hone their 'technical capability for espionage'.

Other projects included cyber-security, covert communications systems and steganography, which is the practice of hiding a secret message in a file or physical object to avoid detection.

The security service alert says: 'MI5 has identified that the primary purpose of CGTRI is to fund academic research that directly improves MSS technical capability for espionage.'

The security service would not name the universities involved. But separate enquiries reveal Cambridge has published a study online which said it was sponsored by the China Academy of General Technology (CAGT), which is another English name for the CGTRI. However, following publication, Cambridge confirmed this was an error and CAGT had not funded the study. It has removed the reference from its website.

The study, published in 2025, was co-authored by a Cambridge academic and was about 'ancient metagenomics', a discipline used to analyse DNA on archaeological samples.

Two academics at University College London (UCL), part of the elite Russell Group, also co-authored a paper in 2023 sponsored by the same body about 'developing carbon-based materials for batteries'.

Now all universities are being instructed to sever ties or academics could face charges for assisting a foreign intelligence service, which carries a possible 14-year prison sentence.

Security minister Dan Jarvis said: 'This alert exposes attempts by Chinese intelligence to covertly benefit from the expertise and research of our academics, undermining our national security and that of our allies.

'I have written to all university vice-chancellors to ensure they support their staff to end all arrangements with this company, preventing further benefit to the Chinese intelligence services and ensuring compliance with the National Security Act.

'International partnerships are vital to ensure our universities and research institutes continue to thrive, but we will take robust action to defend against the threats we face. That means supporting our police and intelligence services to expose and disrupt harmful activity, using the full force of the law.'

Academics may not realise that their work is being funded indirectly by the CGTRI, while some academic institutions will have engaged with CGTRI in 'good faith' not knowing the link to the MSS, MI5 said.

Tory security spokeswoman Alicia Kearns said: 'No British university should be assisting the intelligence service of the Chinese. This is a wake-up call for academics naively telling themselves working with the Chinese Communist Party rises above politics. These universities are making us less safe, abetted by this Government which scrapped free-speech powers giving universities stronger protections on campus.'

Anthony Glees, a security expert at Buckingham University, said: 'Universities are evidently becoming a national security threat right now. There may well need to be an inquiry into how their overspending is now causing them to hand over some of our best research to Beijing.

'The desperate search for cash... has made them sitting ducks for Chinese spying operations.'

When approached for comment, UCL said that one of the researchers involved said the paper was not funded by CAGT. UCL said that despite CAGT being listed as a funder online, it does not appear in the acknowledgments of the journal article.

Cambridge University was approached for comment.

• A previous version of this article said that CAGT had funded a study at Cambridge University. Following publication, Cambridge confirmed that CAGT was listed as a sponsor in error, and removed it from its website. The article has been updated to make this clear.