All three bodies were found at the bottom of the cliffs

Anne Harris, 29, Jamie Hague 19, and Shaun Sheppard, 17, fell to their deaths from 200-feet-high (61 metre) cliffs at Salcombe Hill, near Sidmouth, in June 2002.

They were voluntary patients at the Cedars Hospital at Wonford House in Exeter, run by the Devon Partnership NHS Trust.

There has still not been an inquest, but the independent investigation suggests there was evidence the three had suicidal tendencies and were able to stockpile drugs.

The independent report was compiled by two consultants, one from the Dorset Health Care NHS Trust and another from the South London and Maudsley NHS Trust.

At the time of the incident, there was no dedicated psychology time for the ward where they had been staying at the Cedars unit.

The report said that, on occasions, drugs were being sold through windows at the unit.

The report said drugs were being sold through windows at the unit

It also said says the Devon Partnership Trust should make sure patients under 18 are not admitted to adult wards unless clinicians agree it is the best way to care for them.

Trust medical director Dr Paul Cawthron said: "Substance misuse is very common in mental health and psychiatric units across the country.

"It's one of those things that we are very concerned about and do discuss with local police forces.

"We do have to try to be very careful to make sure, as far as possible, that we don't let a drug-using culture come into the unit."

The report said appropriate lessons needed to be learned from what happened and highlighted the heavy workload being put on existing consultants.

However, it said there needs to be an open no-blame policy.