The cases refer to services provided by the trust in Gillingham and Darent Valley Hospital in Dartford.

A trust spokesperson said the referrals had ‘not been correctly managed in line with NHS waiting time standards' adding: ‘We are very sorry that as a result of this, these patients have experienced an unnecessary delay for their care.'

The referrals include 4,279 adults and children predominantly in the Dartford, Gravesham, Swanley, Bexley and Greenwich areas awaiting a first outpatient appointment and 4,570 existing patients awaiting a follow-up appointment, diagnostic test or procedure in the same area.

The trust said when the referrals had been first received they had been reviewed by a clinician and assessed as routine as no urgent concerns such as cancer were identified.

It said it was contacting patients to apologise and was making arrangements for the patients to be seen as quickly as possible.

The spokesperson added: ‘We have taken immediate action to ensure referrals to this service are correctly managed, with stronger oversight and improved systems in place. A full, independent investigation has been commissioned to understand how the error occurred and if anyone has come to harm as a result of these unnecessary delays. We are committed to learning from this so that it does not happen again.'