Recruiters are casting doubt on whether an urgent review of recruitment checks on overseas staff working in the NHS that has been ordered by Prime Minister Gordon Brown will produce concrete results.

The government action ignores basic challenges facing recruiters and the NHS alike in scrutinising candidates, they say.

Kevin Farr, managing director of medical recruitment firm Jark Healthcare, said: "Even with increased legislation, the crux of this will be criminal checking, and those from overseas can pose real [checking] problems."

Kate Bleasdale, chief executive of medical recruitment firm HCL, added: "If they have got the correct references and qualifications, how can you tell whether they are a terrorist, or not?" she asked. "If you ask someone, 'are you a terrorist, are you going you going to blow somebody up?' , they are hardly likely to say 'yes'." Bleasdale has also alleged that the checks that recruiters are required to carry out on NHS candidates were far more rigorous than those required by NHS Trusts themselves. Bleasdale contends further that the NHS has failed to complete basic vetting procedures on staff before allowing them to work.

"Every single doctor is meant to have a CRB check, and they don't," she alleged. Bleasdale told Recruiter of a case she had seen which showed it was possible for a Trust to appoint a doctor while their CRB was still being processed.

However, a spokesperson for NHS Professionals, the NHS's own staff agency, rejected Bleasdale's contention, saying the agency "would not employ someone before CRB checks had been completed".

The only possible exceptions to staff not being CRB checked prior to starting a new job were those "already in service who were moving around" between Trusts, said Julian Topping, head of work place health and regulation at NHS Employers.

Topping also said that Bleasdale's claim that recruitment agencies must carry out more rigorous vetting procedures than NHS employers themselves was simply wrong. "They are completely the same," he said. "They are both based on the Health Commission's standard."

Topping said that "not being an expert on security" he "couldn't possibly say" whether the NHS's employment vetting procedures were suitable to identify people who might be a security threat to the UK. "They are fit for purpose for what they are designed for - to determine whether a person is fit to carry out their duties in the NHS, but I couldn't say whether they are fit for purpose to determine wheter someone is a security risk," he said.