A professional qualification for aspiring headteachers is ineffective, outdated and not producing enough school leaders, according to a new report.
Estyn inspectors found that too many teachers who take the National Professional Qualification for Headship (NPQH) use it as a form of professional development and have no intention of becoming heads.
Since 2005 all aspiring heads in Wales have been required to hold the NPQH to demonstrate that they have the right skills, knowledge and attributes for the role.
But a report published this week says the qualification has not had the expected impact on headship and has not served its purpose of producing heads within three years of passing.
It says the supply of NPQH holders "far exceeds" the demand for heads in Wales, and the qualification is now held mostly by middle managers.
Figures from the General Teaching Council for Wales show that in 2009 there were 739 NPQH holders who were not heads, compared with 532 who were.
Estyn's report says the selection process for applicants is ineffective because it is "completely reliant" on statements made on application forms, which are not checked, and because local authorities do not interview candidates.
It also says the training programme has not been updated to reflect "contemporary issues" like school inspection, self-evaluation and the School Effectiveness Framework.
Officials at the NPQH Centre, which is run by a consortium of Welsh universities, claimed that poor funding meant they were unable to update the course and that a lack of clarity from the Assembly government made long-term financial planning difficult.
Heads' unions have been sceptical about the value of the qualification for a number of years.
Anna Brychan, director of NAHT Cymru, said: "What it doesn't do is offer the school leaders of the future the kind of training and vision required to tempt them into what school leadership is all about - leading teaching and learning in schools.
Gareth Jones, secretary of the Association of School and College Leaders Cymru, said he found the report's findings "accurate but very disappointing", and praised Estyn for its clear recommendations.
The inspectorate's report says the Assembly government should create a structured programme of professional development, including a mandatory qualification for middle managers that applicants must complete before the NPQH.
It adds that the government should also review whether holders should keep their NPQH status if they have not made consistent efforts to become heads within five years of gaining the qualification.
Ann Keane, Estyn's chief inspector, said: "It is vital that relevant bodies work together to ensure that teachers have a relevant, coherent route to develop the skills and attributes needed to become highly effective headteachers."
The Assembly government welcomed the report, which it said supported its view that the NPQH programme had become outdated and needed to be revised.
"We want to develop a clear leadership programme that will prepare the most suitable applicants to be effective headteachers," a spokesperson said.
`An update is needed'
Mike Pickard, a retired headteacher who is now an NPQH mentor, agrees that the programme needs to be updated.
"I think the programme itself is basically sound, but an update is needed because there have been huge changes in the last couple of years," he says.
Mr Pickard adds that developments such as the School Effectiveness Framework - which requires schools to work more closely with each other and local authorities - have not yet been included in the training.
"My own perception is that the quality of people we get is very high and they are getting very good training and support," he says.