Researchers promise that teachers prepared to ride the embarrassment of seeing themselves on screen will reap the benefits.

They say video and playback techniques, which have long been used by sportsmen to hone their technique, can lead to rapid improvements in teaching performance.

Unfortunately, most teachers seem to view the fly-on-the-classroom-wall exercise as too intrusive. Researchers on the three-year project found that most had never been filmed at work.

Now staff are being urged to give video analysis a try by the teacher who led the school-based exercise, funded by the Teacher Training Agency.

History teacher Patricia Hopkins, from St Thomas More high, Tyne and Wear, said: One teacher with 20 years’ experience had never been videoed, yet she said she learnt more from the exercise than all the appraisals and monitoring she had ever had.”

Teachers were filmed delivering a lesson, then colleagues watched the tape and assessed its good and bad points.

Then teachers were coached before being filmed again. Researchers found there had been a marked progress with the knock-on effect that pupils’ thinking skills had improved considerably.

Ms Hopkins believes video will play an increasing role in professional development. “If cameras are used in an atmosphere of trust they can encourage rapid progress,” she said.

But with the increasing popularity of TV programmes which catch people at unguarded moments, teachers would be well advised to guard the video footage ...