Denise Brewster (pictured outside court) has won an appeal to the Supreme Court after being denied payments from her late long-term partner's occupational pension

A fiancee whose partner died just two days after they got engaged has won the right to access his pension in a landmark Supreme Court ruling which could affect millions of other unmarried couples.

Denise Brewster, from Coleraine, Northern Ireland, argued that she was the victim of 'serious discrimination' when she was denied a 'survivor's pension' because she was not married to her partner Lenny McMullan when he died.

But, after an eight-year legal wrangle, five Supreme Court justices have now unanimously ruled that she is entitled to payments under the scheme.

The decision could pave the way for thousands of other British cohabitees working in the public sector to make similar claims.

While raising money to take her case to the Supreme Court, Ms Brewster, a lifeguard in her 40s, wrote on her Crowdfunding page: 'My case is simple: bureaucratic rules like this which discriminate against long-term cohabitees should not be permitted.

'I had to make a stand for this and this was about our love and what we were for each other.

'It is hard enough trying to come to terms with such a loss, without the additional financial and emotional burden.

'I don’t want another partner to go through what I have gone through.'

The court was told how Ms Brewster and Mr McMullan were together for 15 years and lived together for a decade, including buying a home together in 2005.

On Christmas Eve 2009, they got engaged. But, two days later, between Christmas night and the early hours of Boxing Day, Mr McMullan, 43, died suddenly.

The 42-year-old (left) argued that she was the victim of 'serious discrimination' when she was denied a 'survivor's pension' because she was not married to her partner Lenny McMullan (pictured together, right) when he died

The couple (pictured) got engaged on Christmas Eve 2009. But, two days later, between Christmas night and the early hours of Boxing Day, Mr McMullan, 43, died suddenly

At the time of his death Mr McMullan had 15 years' service with Translink, which delivers Northern Ireland's public transport services.

He was paying into Northern Ireland's local government pension scheme, which is governed by the Local Government Pension Scheme (Benefits, Membership and Contributions) Regulations (Northern Ireland) 2009.

If they had been married Ms Brewster would have automatically shared the pension that he had built up.

If they had been married Ms Brewster (pictured) would have automatically shared the pension that he had built up

But, under the regulations, unmarried partners only received a pension if there has been compliance with an 'opt-in' requirement.

This involves the pension scheme member nominating their partner for payments by giving the Northern Ireland Local Government Officers' Superannuation Committee (Nilgosc) a declaration signed by both partners.

Although she met all the other criteria, Nilgosc refused Ms Brewster a survivor's pension because the committee had not received the appropriate nomination form from Mr McMullan, despite her believing it had been done.

Ms Brewster then took the case, arguing that the system discriminated against her and breached her human rights.

She initially won her case in the High Court in Northern Ireland, where a judge said that it was 'irrational and disproportionate to impose a disqualifying hurdle of this kind'.

She had used crowd-funding to raise the money to bring that case.

However, that decision was then overturned in the Court of Appeal in Northern Ireland before the case headed to the UK Supreme Court for a final decision.

Speaking before the Supreme Court hearing, she added: 'Myself and Lenny both paid into that pension scheme.

'We paid into that scheme for years and neither I nor anyone belonging to Lenny's family were going to be able to avail of that pension fund that we had paid into the pot.

'Lenny and I were planning for our future. We thought we would grow old together. I never suspected that if Lenny died the money he had paid in for us would just be kept by the pension scheme.'