Mr Blair emphasised the importance of leadership in schools

Prime Minister Tony Blair and Education Secretary Alan Johnson announced a wider role for the Future Leaders scheme at a Downing Street seminar.

This project is designed to recruit candidates from outside education into becoming head teachers.

It will also seek to alleviate the growing shortage of head teachers.

The Future Leaders scheme, based on a project in the US, provides hothouse training for a small number of potential heads and deputies - specifically recruited to manage the most challenging schools.

Challenging schools

Mr Johnson spoke of his enthusiasm for a project he had visited in a deprived area of Washington in the United States - where strong leadership had helped to turn around schools from failure into examples of success.

FUTURE LEADERS SEMINAR Blair tells the heads about leadership

And Schools Minister Andrew Adonis, speaking at the seminar, emphasised the importance of having the best leaders in the most challenging schools.

The Future Leaders' initial intake of 20 trainees will now be doubled to 40 for next autumn - with the programme being designed to make these recruits ready to become head teachers within four years.

These trainees, all currently based in London, spend a "residency" year in an inner-city secondary school - as apprentices to an outstanding teacher and with the support of an individual "coach".

In their second year, these trainees will find senior posts in schools - such as deputy headships - accompanied by further training.

Head shortages

The project has also made a virtue of looking beyond education for its candidates - and included in the current trainees are eight former teachers who left the classroom for other careers.

The aim of Future Leaders is to break the cycle of poverty and educational failure - pointing to the contrast between a child from an affluent area having a 70% chance of getting five good GCSEs, while only 30% of youngsters in poorer areas achieve this level.

The project also comes against a background of head teacher shortages.

Speaking at the seminar, head teachers' leader John Dunford warned of the "demographic downturn" - with an ageing teaching profession meaning that a large number of retiring heads would have to be replaced.

The General Teaching Council for England has also warned about the lack of candidates for headships - forecasting that in the next four years there could be 40% of posts left vacant.

The GTC survey, predicting a shortfall, had found that there were only 4% of teachers who anticipated applying for headships - while 34% of existing heads wanted to retire in the next five years.

The Liberal Democrats' education spokesperson, Sarah Teather, warned that the head teacher shortage demanded urgent attention.

"The current headteacher shortage is a looming crisis which threatens our whole education system. And it is a problem entirely of this government's making.