The qualified teachers are being paid up to 40 per cent less than German counterparts despite a European Community directive on cross-border recognition of degrees and professional qualifications.
The European Commission in Brussels has already told Berlin that it is flouting rules at Berlin's two bilingual primary schools.
Charles Dickens and Erich Kstner primaries lost almost half of their English teachers at the end of this school year. Teachers have been poached by private international schools expanding as more diplomats move from Bonn in advance of transfer of government next year. Now parents fear that the bilingual system will collapse.
The EU Commission opened an infringement procedure against Germany early last year after several warnings. The Department of Trade and Industry in London is also backing the teachers' case. The German teachers' union, the GEW, is to take their case to the European Court.
The EU directive says higher education diplomas obtained in a higher education establishment of the different member states are equal. Article 3 allows EU nationals to work on the same conditions as host nationals.
But June McTaggart, a teacher at the Charles Dickens primary, who has failed in her third court case for equal pay, said "Berlin has just thumbed its nose" at the Commission.
Wolfgang Schimmang, head of Berlin's Schools Authority, justified paying German teachers more because "no other European teacher studies for as long as German teachers".
But Ilse Schaad of the GEW, which is providing legal assistance for British teachers, said: "What the Berlin authorities want us to believe is that no one in Europe has qualifications equal to German teachers. It is absurd. "
Mrs McTaggart has 18 years' teaching experience. She said "I am training German teachers earning 40 per cent more than me and I am being told I'm not qualified."
The GEW says it will take the case to the European Court of Justice in Luxembourg.
But even if this case is won it will be too late to stem the flight of teachers from the bilingual schools. And it will also be too late for Mrs McTaggart who left Charles Dickens primary in July to teach in a private international school in Berlin. She said: "I've loved working here. The parents are trying to be European and the teachers are breaking their necks to honour this. But the administration is not showing its commitment to Europe."