Paula McGowan, whose 18-year-old autistic son Oliver died in 2016, was told that at least five members of staff at Bristol Foundation NHS Trust may have accessed his records without permission as recently as this year, the BBC reported.

Bristol NHS Foundation Trust chief nursing and improvement officer, Professor Steve Hams, said: ‘As soon as these potential issues were identified, we took immediate action, including self-referring the matter to the Information Commissioner's Office and undertaking a thorough investigation as a priority.

‘Most of the accesses reviewed have been linked to legitimate clinical or operational activity. A very small number of instances remain under investigation, and it would be inappropriate to reach conclusions before those enquiries are complete.

‘We remain committed to being open and transparent about our findings. Should any inappropriate access or misconduct be identified, appropriate action will be taken through the relevant processes.

‘We have remained in close contact with Oliver's parents throughout this investigation and will continue to keep them informed as our enquiries progress.'

NHS England chief executive Sir Jim Mackey warned in July that NHS staff who inappropriately accessed patient data would be sacked or imprisoned following a string of incidents this year.

In a further incident this week, meanwhile, University Hospitals Coventry and Warwickshire NHS Trust said it was investigating a confidentiality breach.

A spokesperson said: ‘Protecting patient confidentiality is a priority and we treat concerns about inappropriate access to medical records extremely seriously, initiating formal disciplinary action in all cases.

‘All staff are clear that patient information must only be accessed where there is a legitimate reason linked to providing care or carrying out their role.

‘We have systems in place to monitor access to patient records and investigate any issues in line with trust policy.'

The Information Commissioner's Office provdes data protection training for smaller health and social care organisations.