The Law Lords have upheld the decision of a Jewish judge to refuse asylum to a Palestinian woman, denying the claim that the judge's membership of a Jewish jurists' organisation prejudiced her ability to hear the case.

The ruling in the House of Lords reaffirmed a 2007 ruling by the Edinburgh Court of Sessions on the suitability of Lady Cosgrove, Scotland's first female judge, now retired, to act as a "fair-minded and informed observer" in the case of Fatima Helow, a Palestinian woman who survived the 1982 Sabra and Shatila massacre in Lebanon. Mrs Helow was part of the group that in 2002 tried to charge former Israeli Prime Minister Ariel Sharon, in the International Court of Justice, for his alleged involvement in the massacre.

In 2004, Lady Cosgrove as the reviewing judge upheld the decision of the Scottish Home Department to refuse Mrs Helow refugee status in the UK. Mrs Helow's lawyers tried to appeal against the ruling on the grounds that Lady Cosgrove was not an impartial observer due to her membership of the International Association of Jewish Lawyers and Jurists (IAJLJ). The appeal cited speeches by IAJLJ leaders and articles in its quarterly magazine that were highly critical of Palestinian attempts to act against Israel in international courts as proof of Lady Cosgrove's alleged bias.

The appeal was dismissed last year in Scotland and brought before the House of Lords. The five Law Lords rejected the appeal on the grounds that there was no evidence that Lady Cosgrove held partisan views, such as those expressed by other members of IAJLJ. The senior judge, Lord Hope of Craighead, wrote: "There is no basis on which the observer would conclude that there was a reasonable possibility that the judge was biased."

Both Lady Cosgrove and Mrs Helow declined to comment on the ruling.

Mick Napier, chair of the Scottish Palestine Solidarity Campaign, which has been supporting Mrs Helow, said: "There's something wrong when a survivor of Sabra and Shatila is told she cannot stay here after being fully integrated into the Glasgow community, while the man who was seen, even by the Israeli Kahan Commission as responsible for the massacre, Ariel Sharon, was allowed into 10 Downing Street. As to the ruling, there have to be questions on Lady Cosgrove's suitability to sit on the appeal given her involvement in such an overtly Zionist organisation."