Penny Allen, 51, went on the run on Thursday, the day a family court judge in Brittany upheld a ruling that the boy should be returned to his father, who has sole custody.

When she did not turn up at court she was placed on the official police wanted list, sparking an alert at the region's ports and airports.

She was found while on a bike ride in the Brittany town of St Brieuc - 40 miles from her remote farmhouse.

Ms Allen's elder son from her 13-year marriage to Mr McEwan had already returned to Britain from France.

No charges

A statement issued on behalf of the author by his solicitors said: "Ian McEwan was this evening reunited with his son with the assistance of the French police.

"Mr McEwan declined to press charges against Ms Allen.

"He hopes that he and the children will now be able to resume their normal lives in peace and privacy."

Mr McEwan also won a High Court injunction banning Ms Allen and her fiancé, Stephen Ismay Tremain, from disclosing sensitive information about the court proceedings in England and France, as well as secrets about the writer's life.

Mr McEwan, 51, rose to prominence as a short story writer before going on to win prizes for books including Black Dogs. His latest novel, Amsterdam, won the Booker Prize last year.

He married journalist Annalena McAfee in 1997 aftering divorcing Ms Allen and divides his time between London and Oxford.