Teacher shortages could scupper the chances of a key Government education target being met next year, it is claimed.

Schools watchdog Ofsted warned that the search for staff was distracting headteachers' attention from ensuring that the literacy strategy was being implemented properly.

The Government has set a target that 75 per cent of all 11 year-olds must reach the required standard in maths by 2002.

But results this year slipped back a point to 71 per cent and Ofsted chief inspector Mike Tomlinson said it was impossible to predict whether the goal would be achieved.

Ofsted keeps tabs on what is happening in 300 primaries as part of its scrutiny of the literacy and numeracy strategies.

Mr Tomlinson said: "In these schools, there have been examples where schools have had difficulty in replacing staff who have left, they've had difficulty in getting good supply staff which means that in some instances they have a significant number on short term contracts.

"Subject knowledge does need in-service training and very few supply teachers have undertaken training for the numeracy strategy.

"It's the combination of the two which not only affects continuity of teaching and learning but also the confidence of the teachers concerned."

Good knowledge of the subject and the ability to teach it skilfully was the key to maintaining the improvements seen between 1998 and 2000, he went on.

But headteachers had been forced to devote time and energy to finding staff that could be spent on ensuring maths was being taught well.

"Unfortunately, one of the sufferers this year has been the numeracy strategy."

Asked whether the Govern-ment could still meet its maths target, Mr Tomlinson replied: "At the moment, I wouldn't even hazard a guess."

Ofsted said primary schools must do better at teaching their children how to work on their own during the literacy hour.

The proportion of lessons where this is unsatisfactory has risen from one in six to one in five over the last year, inspectors found.

Inspectors also uncovered a worrying trend of weak leadership from heads when it came to the maths hour.

British pupils are near the top of the world league table in maths, English and science, a report shows.

But while the UK came in the top 10 in a 32-country league table of mathematical, scientific and reading literacy scores, research by the Organisation for Economic Cooperation and Development showed it has one of the worst records of any industrialised nation at getting pupils from poor families to do well at school.

In the reading literacy test, Finland came top, followed by Canada, New Zealand, Australia and Korea while the UK was ranked seventh.

Japan was in top place for maths, with the UK eighth, and in science the UK was again fourth.

Germany was in 20th place for both maths and science and 21st for literacy.