Maths test results at a London primary school have been quashed after an investigation into a claim that the children had been helped with their answers.

The decision affects more than 50 pupils at Hanover Primary School in Islington - which only last month was awarded "beacon" status, holding it up as an example to other schools.

Their parents are getting a letter from CEA@Islington, the outside consultancy running Islington's education services, telling them of the decision by the exams regulator, the Qualifications and Curriculum Authority (QCA).

"The QCA has determined that it was not possible to guarantee that the Key Stage 2 maths papers reflected the genuine and unaided work of the children," it says.

School transfers

A decision on the other national curriculum tests, in English and science, is to be made within a week.

Vincent McDonnell, director of schools' services, said the decision should not affect children's entry next term to secondary schools, which would be able to look at internal assessments to see what their abilities were.

Hanover's head teacher for more than two decades, Cynthia Thumwood, was said to be "away for personal reasons".

The school was one of those named in the annual report from the chief inspector of schools in England as being an example of an outstanding primary school.

Its test results make it one of the best in Islington and in recent years have been well above the national average.

On Monday, the QCA said it had annulled all the results of final year pupils at Merstham Community Primary in Redhill, Surrey, amid suspicions that some children had been given extra time to complete the tests.