Participant data from UK Biobank was listed for sale on a Chinese consumer website owned by Alibaba, in what chief executive Professor Sir Rory Collins described as a clear breach of contract by three academic institutions that had been granted research access, according to a statement released by the organisation on April 23.

UK Biobank is one of the world's largest biomedical databases and research resources, holding detailed genetic, lifestyle and health information from 500,000 participants in the UK aged between 40 and 69 when they were recruited between 2006 and 2010. The database has supported thousands of studies across cardiovascular disease, cancer, dementia and other conditions since it began making data available for research in 2012.

The listings were swiftly removed before any purchases were made, with support from both the UK and Chinese governments, Collins said in a message dated this week.

UK Biobank has temporarily suspended all access to its research platform while strengthening security measures. The organisation has imposed a strict limit on the size of files that can be taken off the platform, aimed at allowing researchers to export the results of their research while severely limiting their ability to take de-identified participant data off the platform.

All files exported from the research platform will be monitored daily for suspicious behaviour. A comprehensive board-led investigation into the incident will also be conducted.

"Listings offering access to UK Biobank data (which did not contain any personally identifying information) were found on a Chinese consumer website. These listings were swiftly removed before any purchases were made," Collins said.

The three academic institutions involved and the individuals responsible have had their access to UK Biobank suspended. Researchers are required to conduct research on the restricted, cloud-based research platform hosted in the UK.

UK Biobank has been developing the world's first automated checking system able to prevent de-identified participant data from being taken off the research platform. The automated system is due to be in place by the end of the year.

"We apologise to our participants for the concern this will cause, and we hope to provide reassurance by outlining the serious actions we are taking in response," Collins said.

The data listed on the Chinese consumer site did not contain personally identifying information such as names, addresses, dates of birth or NHS numbers.

The breach comes amid rising international concern about data security involving Chinese entities, particularly in the life sciences and genetic research sectors.

US authorities have previously raised national security concerns about Chinese access to American genetic databases, with several Chinese-linked biotech firms placed under restrictions.