Oxford University professor John Ackrill, a leader in the philosophical and scholarly study of Plato and Aristotle, has died.

Born in Reading in 1921 and educated at Reading School, Mr Ackrill started at St John's College, Oxford, as a Classics scholar in 1940.

The following year he left for war service in the Royal Berkshire Regiment and General Staff, reaching the rank of captain.

He returned to Oxford in 1945 to read Classics, Philosophy and Ancient History.

On graduation in 1948, Mr Ackrill became assistant lecturer in Logic at Glasgow.

He was appointed university lecturer at Oxford in Ancient Philosophy in 1949, but before he took up the post he was given two years' study leave, which he spent in Switzerland and Princeton.

After two years as university lecturer, he became a tutorial fellow of Brasenose College in 1953.

In the same year he met and married his wife, Margaret Kerr, and the couple went on to have four children.

They set up home in Charlbury Road, North Oxford.

In 1966, the university created a statutory chair in the History of Philosophy and Mr Ackrill was elected the first holder.

He held it, while remaining a Fellow of Brasenose, until his retirement in 1989.

He was elected a Fellow of the British Academy in 1981 and an Honorary Fellow of St John's in 1996.

John Peach, a Fellow at Brasenose and friend of Mr Ackrill, said: "He was a very, very upright man whose business in life was the study of moral philosophy.

"All those who have been taught by him, will have memories of him being a very formidable but helpful teacher. A high proportion of the leaders in his field today were taught by him."