David Blunkett announces the class size news on Radio 4's Today programme

The Education Secretary, David Blunkett, said the number of five to seven year olds being taught in classes of more than 30 in England has fallen by 100,000 over the past year.

This appears to mark a step towards delivering a key Labour party election pledge to reduce primary school class sizes.

The government's aim is that no five, six or seven year old will be taught in a class of more than 30.

Mr Blunkett made the announcement shortly before a visit to Colegrave Primary School in east London, which has employed two extra teachers to help cut class sizes.

David Blunkett: letter of thanks to every teacher

"It will be results, and not just good intentions on which myself and colleagues will be judged," he told BBC Radio 4's Today programme.

"This September, now, 100,000-plus youngsters - five, six and seven year olds - will be in lower class sizes due to our class size pledge."

But teachers' unions are warning that a looming shortage of graduates prepared to go into teaching could undermine the government's education policies.

The General Secretary of the National Association of Head Teachers, David Hart, told BBC News: "If you can't recruit teachers in the right numbers and of the right quality, there's no point in simply saying we must limit class sizes because that's good for education. We need to crack the recruitment problem and crack it urgently."

An extra £62m was given to schools earlier this year to help them to meet class size targets, and the distribution of a further £560m is due to be made in the next few months.

This money will be used to employ more teachers and build 600 classrooms to help meet the class size pledge.

Mr Blunkett was accompanied by the School Standards Minister, Estelle Morris, on the visit to Colegrave Primary, a school which is also implementing another flagship education policy, the literacy hour, which requires primary schools in England to dedicate at least an hour a day to reading and writing from this term.

Letter

The Education Secretary is also sending a letter to every teacher and headteacher in primary and secondary schools, thanking them for their efforts to raise standards during the past year and setting out the tasks ahead for the new school year.

In his letter, Mr Blunkett says the forthcoming Green Paper on teaching will give the profession an "historic" opportunity to put an end to 20 years of "drift and declining morale."

A Conservative education and employment spokesman, Damian Green, said the letter was an "expensive gimmick".

"This is another example of the money-wasting tendencies of this government's army of spin doctors," he said.

"David Blunkett has spent a vast amount of taxpayers' money sending 450,000 primary and secondary teachers a letter which only talks about the possibility of pay reform. This money could have been better spent in the classroom."

The full text of Mr Blunkett's letter can be seen here.