Tony Blair conceded yesterday that teacher vacancies were rising, but claimed the problem had been caused by the Government's own recruitment drives.
His admission came as the Tory leader, Iain Duncan Smith, seized on official figures that schools in England and Wales were now 5,076 teachers under-strength – almost double the year before.
The figures, revealed last week by The Independent, prompted accusations that school staffing levels had reached a crisis point.
Mr Blair said: "Teacher vacancies have gone up but part of the reason for that is that there are so many more teaching posts are available."
But in angry clashes at Prime Minister's Question Time, Mr Duncan Smith accused the Government of driving demoralised teachers out of the profession.
The Tory leader said: "The figures slipped out by the Education Department last Friday – they do love Fridays in this Government don't they – show vacancies have almost doubled. Schools were short of more than 5,000 teachers in the last year and they are up from 3,000 the year before."
Mr Blair branded his complaints "nonsense", adding: "There are thousands more teachers in place in this country since we came to office.
"The reason there are vacancies is of course they are recruiting, they have been given additional sums of investment. There are schools in my constituency and your constituency and up and down this country where you can see the new teachers, school buildings and classrooms now."
He challenged Mr Duncan Smith to commit his party to support the Government's levels of investment in education.
"Time and time again we ask you for a commitment from the Conservative Party to support that investment, can we now have it?" Mr Duncan Smith retorted: "Another feeble answer from the Prime Minister."
"The answer which you would not give is that 19,000 teachers left the schools in the last year," he added.
The Tory leader accused the Government of "messing around with exams and piling more paperwork on teachers".
Mr Blair hit back: "I think it is important our children take exams." He added: "The numbers of teachers have gone up for the simple reason I have given – that this Government is putting more money into our schools now."
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