When the bedroom tax was introduced in 2013, Jayson and Charlotte Carmichael never imagined they would one day be challenging the government over the policy in the UK's highest court. Yet they are now doing just that.
Charlotte has spina bifida and uses a wheelchair. Her condition means she needs a specialised hospital bed but, as there isn't enough space for two beds, her husband and full-time carer, Jayson, has to sleep in a separate room. Because of the Bedroom Tax their housing benefit was therefore slashed by 14%.
The couple decided to fight this and had some initial success, with a local tribunal ruling that the policy was in breach of their human rights. But the Department for Work and Pensions (DWP) appealed, and the High Court later dismissed an application for a judicial review, a decision which was upheld by the Court of Appeal. The Carmichaels didn't give up. This week, they are one of five families who are at the Supreme Court to argue that the bedroom tax discriminates against disabled people.
Speaking to Politics.co.uk after leaving court on the second day of the hearing, Jayson Carmichael says their battle has taken its toll on the couple.
"It's always difficult with Charlotte's condition, but all this is making it harder," Jayson says. "I'm sure the stress is making her worse. It's also affected my health, I had a very bad flare up of psoriasis which became infected and left me in hospital for four days. It's all stress related."
Just the trip down to London from their home in Merseyside proved difficult for the couple. Charlotte missed the second day of court as she was so exhausted and Jayson had to rush back to the hotel during a lunch break to check on her.
"It's frustrating for Charlotte," Jayson says. "She wants to be in court but after yesterday we thought we might have to cut the trip short."
In January, the Court of Appeal found the bedroom tax was discriminatory in two cases. That of the Rutherfords, who care for their disabled grandson, and of a woman who needs a panic room because of a violent ex-partner. To the dismay of many, the government refused to accept the court's decision and their appeal is now being heard alongside the other cases at the Supreme Court this week.
Jayson says the fact the Department for Work and Pensions is prepared to drag vulnerable people through the courts to defend a policy which has proved so controversial, is a kick in the teeth for people like them.
"I always knew it would be difficult," he says. "But you can really tell they [the government] have thrown a lot of money at good lawyers to fight this.
"They use all this legal jargon to defend the policy but what it really comes down to is that the bedroom tax is meant to apply to people with a spare room. We don't. I have to sleep in a different room because we have no other choice."
The DWP argue that people like the Carmicahels or the Rutherfords can apply for a Discretionary Housing Payment (DHP) from their local councils to cover the cost of the bedroom tax and so there is no need for an exemption. But local authorities only agree to pay a DHP for up to a maximum of 12 months and then claimants must apply again which, as Jayson points out, leaves them not knowing from one year to the next if their payment could be stopped.
"It's called a discretionary payment and it's just that," he says. "It's down to a council's discretion who should get help. There's a real risk that people like us who are carers or have serious health problems could fall between two stools. It could become a postcode lottery."
Jayson points to the government's recent decision to scrap the benefit cap for full-time carers of disabled relatives, and says he doesn't understand why the same logic is not applied to the bedroom tax.
Today is the last day of the hearing at the Supreme Court but it's likely to be several weeks before we know the outcome. The Carmichaels are worried that, if they lose, they would not only need to find the money to cover the extra rent but that it could also be backdated.
"It would be devastating for us, if that happens," Jayson says quietly. "I would like Iain Duncan Smith to think about how this policy impacts people like us, and ask him to reconsider."