By Gavin Lee,
Audience Reporter, BBC Radio Five Live
Criminal record checks have not been carried out on tens of thousands of NHS staff, including those working with children and vulnerable adults.
Less than a third of trusts admitted all their staff have been vetted
BBC Radio Five Live found 68% of health trusts in the UK do not routinely run checks on staff who began work before the Criminal Records Bureau was set up.
Some 90% of trusts responded to the survey, which came after a listener queried why she was not checked.
The government said it has been developing guidance on the issue.
The listener - who has worked in the NHS for 16 years - contacted Five Live.
She is a child therapist and was worried that despite working in the health service for so long, she had never had a criminal record check.
The woman, whose identity has been protected by the BBC, challenged her local Primary Care Trust (PCT) about this and was told that none of the staff employed before 2002 had been checked.
The reason given was that the cost of doing so was too high.
Any new members of staff employed after the CRB checks began five years ago, are automatically vetted.
The government promised to look again at ways to protect children from adults in positions of trust after the Soham murders.
A report by Sir Michael Bichard recommended a new vetting and barring system, including compulsory CRB checks on existing staff in professions like teaching.
A new system of checks is due to be introduced by the end of 2008, but some experts believe it may take some time to implement efficiently.
Five Live contacted every Trust - or equivalent - in England, Wales, Scotland and Northern Ireland to find out whether the lack of retrospective checks was common.
The BBC received a total of 166 responses to its survey.
In England, 140 out of 151 possible responses were received, with 64% of trusts saying they had failed to routinely run checks.
In Scotland, where all 14 boards responded, 93% said they did not vet all staff - in Wales, where 11 out of 13 trusts gave figures, 91% revealed they not run checks.
The only one of Northern Ireland's five trusts to respond to the BBC's enquiry, said it had not run checks.
Those not being vetted hold a range of jobs, from nursing to GPs and health care assistants. The total number of staff estimated to have no sufficient criminal check is estimated at more than 50,000.
The type of staff employed within a Primary Care Trust includes school and community nurses, therapists, health care assistants as well as a number of doctors and GPs.
The Trusts that have vetted employees say they acted because of the potential risk to patients.
Middlesbrough PCT, for example, said in a statement: "As an organisation, we had identified that there was a gap in the CRB process for staff employed pre-2002.
"We have taken a proactive approach to protecting the interests of the service users and the organisation by ensuring that all relevant staff are systematically CRB checked."
Many of the health organisations which have not carried out checks say it would cost too much and add that there was no guidance from NHS employers to suggest that it needs to be done.
"There has been considerable debate about this issue," Northamptonshire PCT said in a statement.
"At the moment there is no directive to perform checks on existing staff but this may be changing.
"This would cost thousands each year and there is no funding identified within the system to respond to this."
Many of the trusts say staff who were employed before the CRB checks came into force may have been subject to police checks.
However, the failings of the original police checks system were criticised in the Bichard report following the Soham murders, because it was a localised system which did not give details of offences committed outside of each force area.
The CRB system which came into force created a new and more thorough offender register.
Children's charity the NSPCC said: "Dame Mary Marsh, our director and chief executive, is now urging health authorities to prioritise checks on those staff who work most directly with children."
A spokesperson for the Department of Health said CRB checks were mandatory on all NHS workers who come into contact with patients as part of their normal duties and enhanced checks are mandatory for all staff responsible for regular caring, training, supervising or in sole care of children or vulnerable adults.
"We are working with NHS Employers to develop guidance relating to staff who were in post before mandatory CRB checks were introduced."
An NHS Employers spokesperson said a new vetting and barring scheme, to be introduced next year, would enable employers to have electronic access to continuous monitoring of staff.