Its key message - that headteachers should embrace the Government’s educational reforms, and in particular controversial plans to introduce performance related pay for teachers - was carefully leaked to selected Sunday newspapers at the weekend.

While the more serious broadsheets reported that the Prime Minister would use his platform to attack “the forces of conservatism” which sought to oppose his school reforms (returning to his Labour party conference theme), the tabloids led on his pledge to give every new headteacher a free laptop computer, so that they could exchange ideas and best practice with other school leaders.

Thanks to the Government’s spin machine we already knew Mr Blair would underline his message with the words: “The vast majority of teachers do a fantastic job and support what we are doing. But there are forces of conservatism, both inside and outside the profession, who are opposed to change. Headteachers, you are our allies in helping to raise standards for all.”

The speech marks the culmination in a year-long strategy which has put headteachers at the forefront of Government plans to promote a new culture of excellence in schools - with higher pay for successful teachers willing to embrace and promote change, and a greater emphasis on leadership.

Mr Blair underlined his message by announcing that the new national college for school leadership is to be based in Nottingham. Due to be opened next Septembter, it will provide residential training courses and offer information and advice through the Internet.

The announcement came just 24 hours after a National Association of Head Teachers-commissioned survey said that a fifth of schools which advertised for a new head last year failed to find one. Worst hit was London where four in 10 primary schools had to re-advertise vacant headships after failing to receive any satisfactory applications.

The survey raised doubts about the quality - and supply - of applicants. The NAHT said the findings underlined the need for higher salaries and a more manageable workload for headteachers.

Meanwhile, heads in Kent entered the highly-charged political debate over the future of the county’s grammar schools, urging parents to support a petition for a ballot on the future of selection.

The Kent Association of All-Ability School Heads, which represents three-quarters of the county’s secondary schools, has issued a statement opposing selection. Their stance makes clear the view of non-selective heads - who are prevented by law from speaking out individually on the subject - and is a significant blow to campaigners seeking to save Kent’s 33 grammar schools.

The political heat has also been turned up on a number of Kent’s Labour MPs whose children attend local grammar schools. In a Commons debate, Tory spokesman John Bercow accused the Government of “educational vandalism” by trying to close down the country’s remaining grammar schools.

Chief schools inspector Chris Woodhead also found himself subject to criticism during a BBC radio interview when he was asked by a former teacher: “What is half of three-quarters?” Unable to answer, Mr Woodhead admitted: “I’m a total disgrace, but I’m not going to make a complete fool of myself.”