The supreme court has ruled against the UK government’s attempts to force the bedroom tax on 155 partners of people with severe disabilities, in a decision that will hamper ministerial attempts to water down human rights legislation.

A unanimous judgment delivered by the court’s president, Lady Hale, ruled that applying a 14% housing benefit reduction to a man, referred only as RR, was a breach of his right to home under the Human Rights Act.

RR’s partner is severely disabled so “it is accepted” that the couple need an extra bedroom for her medical equipment, Hale said.

Facebook Twitter Pinterest Lady Hale delivers a unanimous supreme court ruling against the government on bedroom tax

The ruling will restore full housing benefit to RR, and at least 155 partners of disabled people who were also subjected to the bedroom tax before rules changed in 2017.

Hale referred to 130 “lookalike cases” in England and Wales and there are known to be 25 similar cases in Scotland. There are also potentially dozens more cases that have not have not been taken to tribunal.

The case has potentially wider implications by bolstering the primacy of the Human Rights Act against any attempt to enforce secondary legislation, like the bedroom tax and potentially other welfare changes, where it can be shown that to do so would breach human rights.

Reading out her judgment, Hale said: “The Human Rights Act is an act of the United Kingdom parliament and takes precedence over subordinate legislation such as the regulation in question … This means that incompatible subordinate legislation must simply be ignored.”

RR in effect took up the case of Jayson Carmichael and his wife Jacqueline, who suffered from spina bifida, after they decided, due to personal circumstances, against appealing against a court of appeal ruling against them in 2018.

Earlier this year, RR was granted a so-called leapfrog certificate to skip the court of appeal and appeal directly to the supreme court against the secretary of state for work and pensions.

Hale said: “This court rules unanimously in RR’s favour. The local authority in deciding claims for housing benefit, the first tier tribunal and the upper tier tribunal in deciding appeals from the local authority, and the courts in deciding appeals from the tribunal, all have a duty under the Human Rights Act not to act in a way which is incompatible with the convention rights.”

A spokesman for the Department for Work and Pensions (DWP) said: “We are carefully considering this ruling.”

Lucy Cadd, a solicitor at law firm Leigh Day who represented RR, said: “This ruling is of great significance because it not only allows for the case of our client and that of the 130 couples whose cases were stayed behind it to be resolved with the social security tribunals disapplying the bedroom tax to ensure none of those individuals suffer a human rights breach, but also because it paves the way for decision-makers to avoid human rights breaches in other areas.”

Carolin Ott, part of the human rights team at Leigh Day, said: “The judgment has potentially wide-reaching effects because it reaffirms the supreme court’s position that subordinate legislation can be disapplied by public bodies and courts where applying that subordinate legislation would lead to a breach of human rights.”

Rosie Brighouse, a lawyer at the human rights campaign Liberty, which was also involved in the case, said: “This decision makes clear what people can expect from their courts and their public bodies when it comes to their duties under human rights law.

“The Human Rights Act exists to enable all of us to uphold our rights, which makes this a major victory for access to justice for everyone in the UK.”

Carla Clarke, the head of strategic litigation at the Child Poverty Action Group, said the ruling meant that households with a medical need for an additional bedroom who had appealed against the application of the bedroom tax to them before the DWP amended the legislation following a successful legal challenge could now have tribunals decide their appeals “in a way which avoids a breach of their right to non-discrimination - in other words, to not apply the bedroom tax to them”.