Hardly any commissioners are carrying out full inspections of private mental health providers despite fears over poor standards, an HSJ poll has revealed.

Of 47 primary care trusts surveyed, only three - Kirklees, Oxfordshire and West Essex - were able to supply clinical governance assessments of independent sector mental health providers carried out within the past two years. East Midlands procurement hub is carrying out a review of low-secure services.

Most PCTs said they monitored individual patients' treatment plans but relied on the Healthcare Commission to check broader service quality.

This is despite a call from the regulator to PCTs to keep a closer eye on private mental health providers.

The plea followed the discovery that almost 15 per cent of them were failing at least five national minimum standards.

Healthcare Commission mental health lead Anthony Deery said PCTs must "wield a lot more clout" or risk missing problems that arose between the commission's inspections, which take place at least once every five years. He said: "We check providers against a set of standards but commissioners should also have a good look around and speak to people about how services run."

Lack of scrutiny was "certainly a factor" in the failure of some providers to hit targets, Mr Deery said.

Mental Health Foundation chief executive Andrew McCulloch said PCTs should be carrying out at least one full inspection every year to examine patient interaction, health and safety, and staff skill-mix.

Meetings held to analyse performance data "tell us nothing", he said, and regulators' reports should be used only for back-up.

A former mental health commissioner, who asked not to be named, said there was a culture of "complacency and cover-up" in PCTs that discouraged rigorous scrutiny. Better monitoring systems were vital, given that a large proportion of mental health patients treated in the independent sector were potentially "dangerous", the source said.

PCT Network director David Stout said: "PCTs recognise they have got challenges around mental health commissioning and there's a long way to go."

But he said commissioners did not routinely visit any type of provider, adding a standard mental health contract, due next April, would strengthen monitoring.

Many children and adolescents and around 14 per cent of adult inpatients are treated in the private mental health sector, which is valued at£845m. Much of the patient data collected by the NHS does not have to be provided by independent sector organisations.

But Steve Trenchard, director of clinical services at The Retreat in York, said regulation of the independent sector was comparable to, if not greater than, that of the NHS.