NHS pension scheme rules which provide for a survivor's pension for a widow or widower but not an unmarried partner are coming under challenge in both the UK and European courts.

Last week the Court of Appeal referred a case brought by a former NHS nurse to the European Court of Justice in Luxembourg. The nurse claims that rules denying her transsexual 'husband' a widower's pension when she dies amount to direct sex discrimination and breach of a European directive on equal pay.

The employment appeal tribunal last year ruled against the nurse, who was protected by an anonymity order in the Appeal Court, following Grant v South Western Trains, in which a railway ticket clerk lost a claim for travel concessions for her same-sex partner. Lawyers for the nurse argue that this conflicts with P v S and Cornwall County Council, in which the court held that sex discrimination laws protecting employees covered transsexuals.

However, the nurse is not herself a transsexual, but the partner of one. Once Luxembourg answers the questions of law posed by the judges, the case will come back to the Appeal Court.

The nurse, whose case is supported by the law reform group Justice and the Equal Opportunities Commission, also claims the denial of a pension for her partner breaches the European convention on Human Rights. Since the Human Rights Act came into force last week, the convention has been part of UK law, enforceable in our courts.

Two other retired nurses, Ken Strank and Roger Fisher, who have been a couple for 40 years, are also bringing a test case under the human rights convention, backed by the civil liberties organisation Liberty.

They claim the denial of a survivor's pension to a same-sex partner breaches protocol 1, article 1 of the convention; the right to peaceful enjoyment of possessions, together with article 14; the ban on discrimination, which includes sexual orientation. 'Possessions' includes the right to a pension.