In a ruling published today (26 June), the ECJ said the UK legislation constitutes direct discrimination on grounds of sex.
The plaintiff, referred to as MB, was born as a male in 1948, but had gender reassignment surgery to live as a female in 1995.
MB was married to a female and claimed the state pension at age 60, five years earlier than the pension age for males – which was the current retirement age at the time.
However, the Department for Work and Pensions (DWP) rejected MB’s application, because she didn’t have a full gender recognition certificate.
At the time of her gender reassignment, UK legislation required the annulment of her marriage before applying for the certificate, since same sex marriage was not permitted.
MB challenged the government’s decision and her case went to the UK Supreme Court, where the judges were "divided" on the case.
The Supreme Court referred it to the ECJ for guidance.
The ECJ stated “that marriage annulment condition does not apply to persons who have retained their birth gender and are married, who accordingly may receive a state retirement pension as from the statutory pensionable age for persons of that gender irrespective of their marital status”.
It added: “It appears, therefore, that that national legislation treats less favourably a person who has changed gender after marrying than it treats a person who has retained his or her birth gender and is married.”
According to reports, MB’s lawyers are "hopeful" the DWP will apply the decision "without delay".
The case will now return to the Supreme Court to apply the ruling.