When Catherine Laylle's husband abducted their children, she expected to get them back. But judges in Germany decided otherwise. Vicky Ward reports on a worrying trend for mixed-nationality families

The autumn of last year: the scene is a courtroom in the German town of Celle, Lower Saxony. Two boys - half German, quarter French and quarter British - sit with their German father. All three avoid the gaze of the woman who sits on the other side of the courtroom.

Despite the pain of finding herself ignored by her children, 41-year- old Catherine Laylle, a senior account executive in a London-based international bank, was quietly confident she would get her children back. Her lawyer had told her that not only was her estranged husband, Peter Volkmann, guilty of breaking German law by kidnapping the boys, he was also guilty of breaking international law - Article 3 of the Hague Convention - by wrongfully detaining them from the custodial parent, Ms Laylle.

Ms Laylle had been granted custody of the boys, Constantin (7) and Alexander (9), after she and Peter had separated in 1992. She took the court a folder from the boys' school in England, the French Lyce, with notes and drawings from the boys' friends telling them they missed them. There were letters from the teachers assuring them of their support and old reports stating how successfully they were getting on with their studies. (Constantin was first in his class, Alexander fifth.) She had letters from family friends testifying how happy the multilingual boys were in England.

The judges did not ask to see anything in Catherine Laylle's folder. She was not called upon to give evidence. Instead, they upheld the father's appeal. The reason? Constantin had told the judges "I am German." The boys said they were frequently taunted as "Nazis" at school in Britain. The judges concluded that "in view of the social and cultural difference ... because the environment is based on a foreign language, since German is not spoken either at school or at home ... since school tuition is demanding ... Constantin's refusal to return to his mother is perfectly understandable." It seemed like a statement of nationalism fashioned to settle what was a family dispute.

It was certainly received in that way. Upon hearing the verdict, Peter Volkmann's family members leapt to their feet, and punched the air, Boris Becker style.

"I did not want to speak out initially about Europe for fear of antagonising the German courts," Catherine Laylle says. "But now, what have I to lose? My case shows that the whole idea of a united Europe, where everybody plays by the same set of rules, is farcical."

Catherine Laylle's case has political and legal implications that go well beyond the average child custody battle. Her case is part of a growing trend within the European Union in which separating or divorcing parents of different nationalities can find themselves penalised by "foreign" courts, despite lip service to the ideal of "European harmonisation".

Recent newspaper coverage could well lead you to believe that similar British child abduction cases by an aggrieved parent occur only in strange and exotic places such as Libya, Turkey and Egypt, when a father or mother wants the child brought up in a certain religion, caste or culture. The truth, however, is that many such cases are found far closer to home.

This year, most famously, has seen the case of Brit award-winning singer Eddi Reader, whose unemployed husband successfully kept their two children in France after their holiday-time expired. The French court found for him - he won custody. He argued that since he was unemployed it would be far better for him to look after the children, rather than a nanny.

Last year the Irish government announced that more than 150 of its children had been caught up in similar cases, while Ireland itself was used as a hideout by Spanish-born Jaime Cabezas-Santana, who kidnapped his three children after an access visit to their Irish-born mother, Jenny Hayes, who lives in Newcastle upon Tyne. She eventually won them back.

Naomi Unwin, from Poole in Dorset, lost her two children to her Spanish husband, Vicente Guerra, because of a ruling by a Spanish court in Palma. The British High Court submitted to the Spanish ruling because under European law she had illegally kidnapped them and brought them to England.

In Catherine Laylle's case, it appears that the German court does not want to play by the same set of rules.

To understand the reasoning of the German judges' decision you need to go back 13 years. Ms Laylle, who is French born but was brought up in England, then had a good City job with a salary of about £40,000 and a company BMW. She met a German doctor, Peter Volkmann, who moved into her flat. They married in June 1984 in London, and in 1985 their first son, Alexander, was born. A year later Ms Laylle decided it would be best for her husband's career (he had lost his fellowship grant) if he took a position in Germany for two years before moving back to London.

Two years became six. Constantin was born in 1987. Ms Laylle was miserable and felt isolated. Her husband became unemployed. The family ended up living in one room in his parents' house. By January 1992 the marriage was dead. Ms Laylle wanted to give herself and the boys a healthier, steadier lifestyle and suggested moving back to London and taking the boys with her.

Peter agreed. A legal document drafted by a German notary stated that both children should live in London with their mother and attend the French Lyce there (they had already attended the French Lyce in Hamburg). They would spend their holidays with their father in Germany. He would pay DM1,020 per month - about £350 a week - towards their support.

The arrangement worked well for the next two and a half years. Ms Laylle found herself a City job. The boys thrived at the Lyce. But then Peter Volkmann, without his wife's knowledge, applied to the Verden court for ex-parte custody of the children. He was refused. When he heard the judgment four days before the children were due to return to London for school last summer, he wrote to his wife saying that he was not returning the children because they did not want to go back.

Ms Laylle hired a lawyer and went to court in Britain. On 30 August the children were made wards of court and the High Court ordered their immediate return to the jurisdiction of England under Article 3 of the Hague Convention.

Yet Catherine Laylle found it impossible to find her children. Mr Volkmann was travelling around Germany with them, presumably in order to escape detection. Still, he turned up to hear his submission in open court in Verden, only to have the judge rule in his wife's favour. Peter asked for half an hour to bring the boys to the courtroom.

But instead of returning the boys, Mr Volkmann went to the nearby town of Celle and lodged an appeal with the superior court. Ms Laylle was stuck in Verden, again searching for her children. She recalls : "It felt like the town was turning its back on me." The police, the bailiffs, the judges: none of them, says Ms Laylle, offered any help.

It took her 24 hours to discover what her husband had done, by which time it was too late. She had to wait for the hearing in Celle on 20 October. She had become ensnared in the German legal system.

Mr Volkmann used the system's loopholes well. Article 13 of the Hague Convention states that children do not have to be returned to the custodial parent if doing so would inflict physical or psychological damage or, more crucially, if they express a desire not to go. Even then, the child has to be deemed sufficiently mature to make such a momentous decision.

Mr Volkmann got a psychiatrist friend of his neighbours to write a report on the boys' state of mind. It said they strongly wanted to remain in Germany with their father. It was this that the Celle judge read. Ms Laylle was stunned: "I may be foreign to the judges, but cannot imagine how I could possibly be a 'foreigner' to my own children."

Ms Laylle appealed to the only court left: the German Constitutional Court. It has around 15,000 applications a year and dismisses 90 per cent of them. It takes between two and 10 years to get a hearing. Her appeal was rejected last February.

Since the Celle ruling, Ms Laylle has had access to her sons only under the supervision of social workers. In 10 months she has seen her boys for no more than three and a half hours. She made an abortive trip to see them as they emerged from school one day, only for them to be bundled into their father's car. In February Peter applied to the Verden court for full custody of the children.

At this point the German justice ministry intervened in the case. After an enquiry from the British Lord Chancellor, his counterpart in Berlin wrote to the Verden court asking it whether it would uphold European law, which says a German court should recognise decisions made by an English one.

The Verden court (which, in a federal state, has ultimate authority over its own proceedings) was not impressed. It ruled in Peter's favour. Ms Laylle is now forbidden from seeing Alexander and Constantin for three months and then only if they are willing to meet their mother. She is not confident their father will ever allow them to say that. Peter Volkmann will not comment upon the case.

"I am not going to give up," she says. "If I, a fighter, cannot get my children back, what hope is there for there for anyone else? I just want a judge to read the view of an independent psychologist. I just want justice."

In that quest, she now has the support of leading Eurosceptics including Tory MP Bill Cash and Labour's Kate Hoey. The latter is succinct: "I think it is a clear breach of international agreement, and our Lord Chancellor should make direct representation to his German equivalent. It puts a cart and horses through any idea of European agreement. But I think it is probably fairly symptomatic of German feeling."

Catherine Laylle is having trouble understanding this. She holds up a letter she has written to Chancellor Kohl seeking his support. She quotes: "My children, as myself, typify the new Europe you are so actively promoting. They are fluent in three languages and have always had a totally cosmopolitan upbringing. Yet a High Court in Lower Saxony decided not to return the abducted boys to their British mother on the strength of four words uttered by a nine-year-old: 'Ich bin doch Deutscher'.

"I have deep respect for the German legal system, but all of us involved in this strongly feel that a miscarriage of justice has been committed. A man has defied both English and German court orders ..." Catherine Laylle's voice cracks. "Please, please help," the letter ends.

So far, she has not had a reply.