Primary deputy head posts should be made temporary in a bid to force experienced deputies to apply for headships, according to the leading education recruitment analyst.
John Howson, of Education Data Surveys, which is owned by TES parent company TSL Education, says this is the only way to ensure there are enough candidates to deal with England's shortage of primary heads.
But he believes that the growing number of more junior, inexperienced teachers could adversely affect the profession in the long term.
By studying all the job advertisements that appeared in The TES throughout 2008, Professor Howson found that more than a third of primaries were forced to readvertise headship vacancies because a lack of suitable candidates.
In total, 2,041 primaries advertised for heads during 2008, the lowest number since 2005.
And 37 per cent of these primaries were forced to readvertise the vacancy within the same year.
Professor Howson points out that around 1,100 primaries have closed or amalgamated over the past decade. This means that, while there were more vacancies in 1999, the overall proportion of primaries advertising for a head increased from 8.2 per cent a decade ago to 11.8 per cent last year.
"The percentage of primary schools experiencing difficulty in recruiting a head remains unacceptably high," Professor Howson said.
Meanwhile, he said, the overall number of deputy heads has fallen from 21,600 in 2001 to 18,700 in 2008, a drop of 2,900 - 2,500 of which are primary posts. As a result, there is a smaller pool from which to draw potential new heads.
Professor Howson suggests that all primary deputy headships should be made temporary posts, lasting five years. By the end of that period, the deputy would be expected to have secured a position as head. Anyone wanting to remain a deputy would need to reapply.
"In this way, the pool of would-be heads could increase," he said. "And any decline in applications for deputy headships would serve as an early warning that teachers did not want to progress to headship."
But Steve Munby, chief executive of the National College for School Leadership, insists that his college's National Professional Qualification for Headship is sufficiently effective at encouraging deputies to move quickly on to headships.
"Finding and recruiting tomorrow's heads is our number one priority," he said. "We are working closely with local authorities and schools across England to make sure the best of the best get into headship."
But, he concedes: "While much is already being done in primaries, we recognise that there is still more we can do."
The Government's prediction that a significant number of experienced teachers are likely to retire in the next two years has led Professor Howson to believe that the profession will become increasingly dominated by less experienced teachers.
In particular, the number of career-switchers is increasing, with a third of new teachers now over the age of 30. The economic downturn may well exacerbate this trend.
"There is an imperative for planners to consider the longer-term needs of the service," he said. "It is incumbent upon policymakers to remember their duty to provide for the needs of school leadership in 10 and 20 years' time. The leadership of the nation's state-funded schools is not something to be left to chance."
But the Department for Children, Schools and Families insists that nearly a third of teachers say they would like to become heads, with 8 per cent claiming they would like this to happen within the next three years.
A spokeswoman for the department said: "The vacancy rate for heads remains low. We know that when deputies have a chance to step up, they enjoy the role and want to become heads."