Three weeks ago Ms Allen went on the run with the two boys from the couple's dissolved marriage. The eldest boy, 15, returned to his father last week.
At a short hearing yesterday morning the French judge told Ms Allen he had no choice but to respect a judgment by Oxford County Court which gave Mr McEwan permanent custody of both children. The decision brings a temporary halt to a public dispute between Ms Allen and Mr McEwan over custody arrangements.
Mr McEwan's lawyer, Jane Craig of Manches & Co, said Mr McEwan hoped Ms Allen would fully comply with the order. She said: "Ian feels very strongly that it's better for the children to have a good relationship with both parents. He wanted her to adhere to the original co-parenting order because that was the arrangement which was best for the children." Ms Craig added: "If she wants to change the order she should appeal and not take the law into her own hands."
But Ms Allen said she still hoped her actions would prompt the Home Secretary, Jack Straw, to launch an inquiry into the case. Earlier this year Ms Allen wrote to the Lord Chancellor in an attempt to overturn a judgment that gave the author temporary custody of the children. The Lord Chancellor has declined to intervene and Mr Straw is yet to respond. While Ms Allen was prepared to break the law for her children she said she was not prepared to go to prison. At the beginning of the saga Ms Allen said she did not want to "prolong the uncertainty" for her children, but, she added, as a "responsible parent" she had had no choice.
The drama first came to public attention when Ms Allen informed the press in a written statement on August 15 that she would not be complying with the Oxford County Court order which gave Mr McEwan sole and permanent custody of the children. As the court deadline for the return of the children expired on midnight of 16 August they were whisked into hiding. Ms Allen's fiance, Ismay Tremain, with whom she lives in Brittany, held the fort at the farmhouse and waited for the press and the gendarmes, whoever arrived first.
Ms Allen then took the children on what she described as a "short holiday" in north-west France, making calls to the press from phone boxes whenever she could. After the eldest boy returned to Oxford to join his father on a planned holiday in Botswana, Ms Allen reappeared at the farmhouse with the younger boy to face the music.
She found her former husband had acted expeditiously, instructing his lawyers to do all that was ever necessary to bring back his son. London solicitors Manches & Co contacted the Official Solicitor and made full use of the Hague Convention, the international agreement which provides for the return of children who have been abducted in breach of a country's court orders.
Mr McEwan also instructed top Paris lawyers who served Ms Allen with a court attendance order last week. In a last-ditch attempt to keep her son she asked the court to give her more time to read the legal papers. The judge agreed but at yesterday's adjourned hearing he was not prepared to make more concessions and finally granted Mr McEwan his order.
Ms Allen and Mr McEwan were married in 1982. The custody dispute has continued since the marriage was dissolved in 1995. Mr McEwan has now married journalist, Annalena McAfee.
Until August this year Ms Allen had a joint custody- arrangement with Mr McEwan concerning the residence of the children. But it was Ms McEwan's decision to make a permanent move from her Oxford home to start a new life as an alternative therapist in Brittany, which prompted a variation in the court order. Mr McEwan claims it was at this point that Ms Allen should have made her objections known. Instead she did not attend the Oxford court hearing which set the new terms of the residency order.
Ms Allen said she could no longer afford to hire lawyers to represent her. Mr McEwan has been able to call upon a top firm of London solicitors and appoint Paris advocates for the French court appearances, but Ms Allen has represented herself.
Mr McEwan, who first rose to prominence as a short story writer, won the Booker Prize with his 1998 novel Amsterdam. His novel A Child in Time, which is to be made into a film, describes the pain after a father loses his child at a supermarket. Throughout Ms Allen's conversations with the press she has suggested that much of his work has been inspired by their relationship, or based on material from her teenage experiences.Reuse content