The defect, which occurred last year in machines made by Trinity Biotech with around 55,000 people needing to be retested, was revealed following a BBC investigation.

An NHS spokesperson, said: ‘This is a historical technical issue and all NHS laboratories affected have either replaced these machines or implemented local quality assurance processes.

‘Anyone requiring a repeat test will be contacted by their GP or local hospital and analysis of national data shows the excess diagnoses of type 2 diabetes seen in the affected sites in 2024 has returned to normal levels.'

The 18 trusts are: Bedfordshire Hospitals NHS Foundation Trust; Norfolk and Norwich University Hospitals NHS Foundation Trust; West Hertfordshire Hospitals NHS Trust; Mid & South Essex NHS Foundation Trust; Chesterfield Royal Hospital NHS Foundation Trust; Barking, Havering and Redbridge University Hospitals NHS Trust; Health Service Laboratories on behalf of the Royal Free Hospitals Group; Synnovis on behalf of King's College Hospital NHS Foundation Trust and Guy's and St Thomas' NHS Foundation Trust; South Tees Hospitals NHS Foundation Trust; Hull University Teaching Hospitals NHS Trust; Calderdale and Huddersfield NHS Foundation Trust; County Durham and Darlington NHS Foundation Trust; Integrated Pathology Solutions on behalf of Airedale NHS Foundation Trust; Stockport NHS Foundation Trust; Maidstone and Tunbridge Wells NHS Trust; University Hospitals Bristol and Weston NHS Foundation Trust; and Gloucestershire Hospitals NHS Foundation Trust.

Kevin Sargen, medical director at Chesterfield Royal Hospital, which confirmed that 2,100 people need to be retested, said: ‘As soon as we were aware of the faulty analyser, we withdrew it and sent all our samples to another laboratory. We prioritised the reassessment of clinical advice given to affected patients to ensure their safety and well-being. Under our duty of candour – and as it is the right thing to do – we contacted and supported all relevant patients working with their GPs. Patients have now been recalled as per clinical priority.'

Tracey Bleakley, executive managing director of Norfolk and Norwich University Hospital NHS Foundation Trust (NNUH), said around 200 patients required retesting having been given an incorrect diabetes diagnosis between 10 June 2024 and 25 November 2024.

‘We continue to work with the ICB and primary care colleagues to ensure this happens as quickly as possible,' Bleakley said. ‘I can confirm that the equipment is no longer used at the NNUH due to a routine equipment upgrade.'