The shocking findings were made during inspections by the Human Tissue Authority (HTA).

A spokesperson for the HTA said: 'The management of the deceased in some licensed mortuaries was identified as a concern through the HTA on-site inspection process.  The deceased should be stored at temperatures that preserve their condition and there should be sufficient storage provision and alternatives in place if needed.

'We expect all licensed establishments to be compliant with our standards and ensure the dignity of the deceased is maintained.  When we find shortfalls we work with establishments to ensure an action plan for improvement is put in place, lessons are learnt and the issue is escalated within the establishment where necessary.'

The HTA cited a number of cases where rules were not being followed due to a lack of resources.

At King's College Hospital in London and John Radcliffe Hospital, part of Oxford University Hospitals Trust (OUH), inspectors found several adult bodies had been stored in excess of 30 days in fridge units due to a lack of long-term storage capacity in 2022.

Also in 2022 'two bodies in an advanced state of decomposition' were found at the Royal Blackburn Hospital, part of East Lancashire Hospitals Trust, after they weren't moved into freezers soon enough.

In 2023, at Leeds General Infirmary, part of Leeds Teaching Hospitals Trust, a body was found that had been in storage for 70 days without being frozen.

King's College Hospital NHS Foundation Trust said it had 'significantly increased' its mortuary provision since the HTA inspection.

An OUH spokesperson said the trust's mortuary had 'recently been refurbished and expanded to increase its capacity in the context of rising regional and national demand for mortuary facilities'.

An East Lancashire Hospitals Trust spokesperson said two people with no next of kin awaiting a funeral were still at its the mortuary because its freezers were at capacity when inspectors visited in 2022.

Chief medical officer of Leeds Teaching Hospitals Trust, Dr Magnus Harrison, said improved systems had been put in place since the inspection, adding Duty of Candour procedures were followed when next of kin information was available.