Teachers will end up leaving the profession due to "immense pressure" if plans to double the number of Government inspections go ahead.

The Government's education watchdog, Ofsted wants to halve the gap between inspections from six to three years.

It also plans to slash the advance notice that must be given before inspectors move into a school, from 10 weeks to one working day.

Chief inspector David Bell said the changes would enable Ofsted to "present a warts and all picture of schools as we find them, not how schools wish to be found".

But Clive Hallett, headteacher of Wheatley Primary School and Oxfordshire secretary of the National Association of Headteachers, said: "It is absolutely appalling and I'm glad I'm retiring in two years.

"In the first instance, Ofsted was meant to inspect the 10 per cent of schools known to be failing. Now all they do is create fear and havoc wherever they go.

"Things have moved on in education in the last few years and most Ofsted inspectors aren't up to date with what is going on.

"Teachers will say 'blow it, I'll go and do something else' if this goes ahead because the pressure on headteachers and teachers during Ofsted inspections is immense."

Under the new proposals, inspections would be shorter, focusing on core subjects, including English and maths. Ofsted reports would be cut from 80 pages to a maximum of six.

Mr Bell has launched a two-month consultation into his proposals, which will require changes to the law if they are to be implemented.

If MPs agree to find time to discuss the plans in the next parliamentary session, "shorter, sharper" inspections could start in autumn 2005.