Last week, the Supreme Court of the UK handed down its judgment in the case of a trans woman known only as MB (as the court protected her anonymity).

MB was suing the Department of Work and Pensions (DWP) for refusing to pay her state pension in 2008 when she turned 60 (which was then the state pension age for a women) and withholding it until she turned 65, as if she was a man. The DWP believes that to get her pension she had to end her marriage (against her strong religious views), obtain a Gender Recognition Certificate and (if they wanted) then enter into a civil partnership with her former wife (this all pre-dated the Marriage (Same Sex Couples) Act 2013).

The Supreme Court was divided and so referred a question about the case to the European Court of Justice in Luxembourg.

The case is in some ways very specific to MB’s marital situation and religious views, but was also an important test of the UK’s commitment to diversity and inclusivity, in particular in relation to the recognition of gender reassignment.

Pensions is one of the few areas where the state still treats men and women differently (although the difference is gradually being removed); other areas range from prisons all the way to use of toilets (which had also been troubling the US courts recently). It’s therefore a key area where the UK government’s respect for gender identity manifests itself.

Several trans woman have already sued the DWP over their pensions, and there are potentially hundreds of others affected. Some of these cases have been put on hold while the outcome of MB’s case has been awaited.

The UK has historically been very slow off the mark in respecting and recognising gender reassignment. In 1970, the High Court annulled the marriage between Arthur Corbett and the model April Ashley on the grounds that Miss Ashley had been born male and the law would not recognise change of gender (Corbett v Corbett).

That remained the basic position for many years until the entry into force of the Gender Recognition Act 2004, which made it possible to have gender change recognised for all purposes (including marriage) if one obtained a Gender Recognition Certificate – which required that any existing marriage be terminated. The act was passed after decisions by the European Court of Human Rights (Goodwin) and the House of Lords (Bellinger v Bellinger) that the UK’s position on gender reassignment was no longer compatible with the UK’s commitment to human rights, and so the law needed to be modernised.

Meanwhile, the issue was also being considered under EU laws which prohibit discrimination in areas like social security benefits, including state pensions. Considering another UK case that was referred to it (Richards), the European Court of Justice held that it was discriminatory to refuse a state pension at the female age of 60 to a woman who had completed gender reassignment surgery. Several years later, the Court of Appeal held that it was equally discriminatory to do so on the ground that the woman remained married (Timbrell).

However, the DWP believes that it is no longer discriminatory under the Gender Recognition Act 2004. It is ironic to say the least that the DWP’s position is now that the Gender Recognition Act actually restricts recognition by requiring divorce or annulment, when that wasn’t required before the Gender Recognition Act. Where an individual is physically, socially and psychologically a woman, as recognised by the state in her passport and driving licence (and in many cases by NHS gender reassignment surgery), why should she be required to end her marriage to claim her pension?

We can expect an answer from the European Court of Justice in around 18-24 months, which will be around a decade after the case first arose. This is not infrequent in complex cases involving issues of social justice, which often take years to make it up to the highest courts on a point of principle.

Given these complexities, pro bono (free) legal representation is crucial for the pensioners in these cases, who are typically not well off, meaning that for them five years of a state pension represents a significant loss with severe financial consequences.

The law is this area is very complex and the cost of hiring a lawyer would be prohibitive for them. It’s therefore been very important to them that Arnold & Porter and other lawyers, including MB’s barristers Lord Pannick QC and Kerry Bretherton QC, have acted pro bono for individuals seeking recognition of their gender in this and similar cases.

Dr Christopher Stothers is an IP litigation partner at Arnold & Porter who represents MB pro bono.