National newspaper league tables of schools' A-level results have been discredited by education chiefs in Oxfordshire.

Tables published in the Daily Telegraph and the Daily Mail yesterday listed secondary schools across Britain in rank order. But several previously successful Oxfordshire schools failed to appear anywhere on the lists.

In the Daily Telegraph, Lord Williams's School, Thame, was the only Oxfordshire School to make it into the paper's list of the top 300 state schools nationally.

The data was compiled by contacting the 1,000 schools considered most likely to be the top performers and relying on staff to return their results. Several Oxfordshire schools appeared on the Daily Mail tables of 550 schools across the UK. Wheatley Park School was ranked at 280 and Lord Williams's School, Thame, was at 342. Banbury School was ranked at 365, Henry Box School, Witney, at 447, Cheney School, Headington at 449 and Matthew Arnold School, Cumnor, Oxford, at 503.

But the Daily Mail also relied on schools returning their own data by the newspaper's deadline.The majority of schools in Oxfordshire, including some with a previously strong academic record, did not appear in the table at all.

County education spokesman John Mitchell said: "We would advise that they're treated with caution. The fact that a school does not appear does not mean anything at all - it's a process of self-selection."

He added: "Oxfordshire has a comprehensive system with mixed-ability intake to all its schools. It can therefore be misleading to compare results of our schools with those which have selective entry."

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