A slimming clinic has been criticised for giving patients unlicensed weight-loss pills and failing to warn of potentially serious side effects in a damning report by the health watchdog.

The Care Quality Commission (CQC) concluded Kings Private Clinic in Maidstone was not providing safe, effective or well-led care in accordance with the relevant regulations.

Inspectors said there was no clinical evidence the drugs prescribed there - diethylpropion hydrochloride and phentermine - would aid weight loss.

It added these were not recommended by the National Institute for Health and Care Excellence or the Royal College of Physicians.

In any case, they were described as a supplementary treatment for patients with moderate to severe obesity only and intended for short-term use.

The independent King Street centre, which gives patients advice on diet and lifestyle as well as medicine, also prescribed unlicensed medicines said the a report, which has only just been published following a visit in February.

The government says these may only be supplied where there are valid special clinical needs and there is no suitable licensed medicine available.

In its report, the CQC said: “Treating patients with unlicensed medicines is higher risk than treating patients with licensed medicines because unlicensed medicines may not have been assessed for safety, quality and efficacy.”

Inspectors found written information provided to patients about their medicines was either incorrect or incomplete.

One leaflet told patients they were “completely safe” taking the prescribed drugs, but health chiefs actually found they can have potentially serious side effects that patients must be aware of.

The clinic’s registered manager, Denise Michael, said: “Everything the CQC highlighted has been actioned and addressed through the proper channels and we are now awaiting a final report.”

The clinic will be monitored until the CQC is satisfied the necessary changes have been made.