'My daughter got a £10,000 council tax refund after living with multiple sclerosis for years' – here's how to check if you can do the same

The SMI discount – which is available in England, Scotland and Wales – is something we've been campaigning to raise awareness about for years. Where you're eligible, you'll be disregarded for council tax purposes, meaning potentially £100s being knocked off your bill and in some cases a backdated payout worth £1,000s.

See our How to claim the 'severely mentally impaired' council tax discount guide for full details. There are also a host of other reasons you could qualify for a reduced council tax bill, such as being a full-time student, live-in carer or on a low household income. Read about these in our Council tax discounts guide.

'I was inspired to apply after watching Martin's show'

Ronnie, 65, and his wife successfully applied for the so-called severely mentally impaired (SMI) council tax discount on behalf of their daughter Leanne (whose name has been changed for privacy reasons), 41, after hearing about it on ITV's The Martin Lewis Money Show in October last year. 

Leanne – who lives by herself in East Lothian, Scotland – was first diagnosed with multiple sclerosis at the age of 19. The disease became so severe that it began to affect her cognitive ability in 2009, after which she was forced to give up working.

Initially, East Lothian Council waived Leanne's council tax bills going forward and refunded her £940 – the equivalent of the 2022/23 tax year's payments. But after hearing Martin say that council tax refunds could be backdated for many, Ronnie duly contacted East Lothian again this January with further documentation.

The council agreed to refund Leanne all the way back to 2013 when she moved out of her parents' home and into her current property. This meant her total refund rose to £10,300 – money she received this April. Ronnie said the application process had been "pretty straightforward" and he hopes this will encourage others who also think they're eligible to apply.

Ronnie said: "As her parents, we've tried to keep the wolf from her door, but this money and the savings going forward are immense. The money will help our daughter in future, and also allow her to plan a family holiday with the rest of us. We can only thank you from the bottom of our hearts for all you do."

The SMI discount is often under-claimed – don't assume you won't be eligible

You may be able to apply for the discount if you have dementia, severe learning difficulties or a similar permanent health condition

By law, someone who has been medically certified (usually using an official form) as having a permanent condition that affects their intelligence and social functioning – such as dementia (including Alzheimer's), severe learning difficulties, or being a stroke sufferer (other conditions may also apply) – can be disregarded for council tax purposes in England, Scotland and Wales. 

This disregard is on the basis of that person having a severe mental impairment – though the name itself is a horrid one. 

Where you've been diagnosed by a medical professional as having an SMI and you are eligible for one of a number of qualifying benefits, you should be able to apply for an SMI council tax discount. 

Those eligible for the SMI discount can claim:

• A 100% discount. If they have a severe mental impairment and live alone.

• A 50% discount. If they have a severe mental impairment and live with other people who are also disregarded for council tax purposes.

• A 25% discount. If they have a severe mental impairment and live with one other adult who isn't disregarded for council tax purposes. (There is no discount if the person with a severe mental impairment lives with more than one adult not disregarded for council tax purposes.)

If successful, the SMI discount can wipe £100s off a council tax bill each year, or even reduce it to zero where the claimant lives alone – and often results in backdated refunds worth £1,000s on top. However, there is no universal rule when it comes to backdating, so if you can get a backdated payment – and how big – will depend on your local authority.

Full details on exactly how the discount works – such as what evidence you'll need and how to apply – can be found in our Severe mental impairment discount guide.

If you live in Northern Ireland it's not possible to apply for an SMI discount as the country uses a completely different system to council tax. Instead, you might be able to apply for a similar discount, known as the disabled person's allowance.

We've seen many life changing SMI successes over the years

Since we began raising awareness of the SMI discount in 2016, many people have been in touch with details of successful applications.

Only last year, we reported one of the biggest SMI rebates we've seen, after a reader contacted us to say their 98-year-old mother-in-law, who has dementia, had been awarded a £15,000 council tax refund.

If you've got an SMI success to report, please let us know.