Who qualifies?
For the SMI disregard, the person must meet BOTH conditions:
Condition 1 — A medical diagnosis
The person has a permanent severe mental impairment of intelligence and social functioning. This is a legal phrase from the Local Government Finance Act 1992. Conditions that typically qualify (this is not an exhaustive list — ultimately the GP confirms severity):
- Dementia — Alzheimer's, vascular dementia, Lewy body, frontotemporal, mixed dementia
- Severe and lifelong learning disability — including Down syndrome with significant cognitive impact
- Severe and chronic schizophrenia with permanent cognitive impact
- Stroke leaving permanent cognitive impairment
- Parkinson's disease with associated dementia or cognitive impact
- Multiple sclerosis with cognitive impact
- Severe traumatic brain injury
- Huntington's disease
- Long-term effects of chronic alcohol misuse (e.g. Korsakoff's syndrome)
Condition 2 — A qualifying UK benefit
The person must be entitled to one of these benefits (whether or not they actually receive payment):
- Attendance Allowance — any rate (lower or higher)
- Personal Independence Payment (PIP) daily living component — any rate
- Disability Living Allowance (DLA) care component — middle or higher rate
- Universal Credit with limited capability for work (LCW) or limited capability for work-related activity (LCWRA) element
- Employment and Support Allowance (ESA)
- Severe Disablement Allowance
- Incapacity Benefit
- Income Support with a disability premium
- Working Tax Credit with a disability element
- Constant Attendance Allowance or Unemployability Allowance (industrial injuries / war pensions)
If the person has dementia and Attendance Allowance — you qualify
The single most common UK combination that unlocks SMI disregard is dementia diagnosis + Attendance Allowance. If a relative has both, you qualify. Apply this week. If they have dementia but no AA, apply for both at the same time — see our
Attendance Allowance guide (worth £3,800-£5,700/yr tax-free on its own).
How much you save
It depends on who else lives in the property. Council Tax is calculated based on adults counted in the household — the SMI-disregarded person is no longer counted.
If the SMI person lives ALONE
100% Council Tax exemption — the bill drops to £0. The disregard makes the property "no adults", which means full exemption under the LGFA 1992.
If the SMI person lives with ONE other adult
25% single-person discount — because the household is treated as having one adult instead of two. UK Band D average 2025/26 is ~£2,170/year — so 25% off is about £540/year saved.
If the SMI person lives with OTHER disregarded people only
For example, an SMI person living with a full-time student or a qualifying carer. The household is treated as having no counted adults — usually a 100% exemption, sometimes a 50% discount depending on the combination.
Worked examples
- Person with dementia living alone, Band C: typical bill ~£1,940/yr → bill becomes £0. Saves £1,940/yr.
- Person with dementia + spouse who is full-time carer, Band D: spouse may also qualify as a Carer disregard — both disregarded → 100% exemption. Saves ~£2,170/yr.
- Adult with severe learning disability living with parents, Band D: the disabled person is disregarded → household treated as 2 adults → 25% single-person discount → saves ~£540/yr.
- Two siblings with severe learning disability sharing a flat, Band B: both disregarded, no other adults → 100% exemption → saves ~£1,690/yr.
How to apply
- Get the medical certificate. Ask the person's GP (or the diagnosing specialist) to complete the SMI medical certificate. Most councils have a specific form they send out. The GP confirms that the impairment is permanent and severe. Most GPs do this free; some charge a small admin fee (typically £20-£40) — but the saving is far bigger than the fee.
- Get the qualifying benefit evidence. A copy of the most recent DWP award letter for Attendance Allowance, PIP, DLA, UC, ESA, IS or whichever benefit applies.
- Find your council's SMI form. Search 'severe mental impairment Council Tax discount [your council name]' or 'Council Tax discount disregards [your council name]'. Or call the council's Council Tax team directly — they have to help you under the Local Government Finance Act 1992.
- Submit both documents — medical certificate + benefit award letter — plus the completed council form.
- Explicitly ask for backdating in the application. Use the wording: "Please backdate the SMI disregard to the date of entitlement to the qualifying benefit, in accordance with the Local Government Finance Act 1992."
- Wait 4-8 weeks for the council to process. You should receive: a new Council Tax bill showing the ongoing discount + a refund of overpaid Council Tax (paid into your bank or credited against future bills).
If the council refuses or under-pays the backdated refund
You can challenge through the council's complaints process, and ultimately the Valuation Tribunal Service (free, independent, run by Ministry of Housing). Alzheimer's Society Dementia Connect (0333 150 3456, free) and Money Saving Expert's SMI guide have campaigned for consistent national backdating. Get free support from
Alzheimer's Society,
Age UK (0800 678 1602), or Citizens Advice (0800 144 8848).
The backdating refund
This is the part most families miss. The discount can usually be backdated to the date the person became entitled to the qualifying benefit — which is often years before the family discovered SMI disregard existed.
What does this mean in practice?
- If a relative has had dementia + Attendance Allowance for 3 years, a typical council backdates the SMI disregard by 3 years — refunding 3 years of overpaid Council Tax.
- For a Band D household where the SMI person lives alone, that's ~£6,500 refunded (3 × ~£2,170).
- For a Band C household with one other adult, that's ~£1,500 refunded (3 × ~£490).
- Some councils backdate even further if the GP can date the diagnosis itself.
Councils vary widely. Some backdate generously; some only to the date of application; some only to the start of the current tax year. Always ask in writing. If refused, ask why in writing — the explanation often helps you escalate to the Valuation Tribunal.
Never pay a "Council Tax refund" company for this
UK companies advertising "we can get you a Council Tax refund — 30% of whatever we find" exist. They typically just apply for SMI disregard on your behalf — and take 25-40% of the refund. You can do this yourself for free in about an hour. Don't lose £1,000+ of a vulnerable relative's refund to a middleman. Citizens Advice will help you apply for free on 0800 144 8848.
Other cascades if SMI applies
If someone in your family qualifies for SMI disregard, they may also qualify for these other UK money routes. All worth checking:
- Attendance Allowance £3,800-£5,700/yr — for over-65s with care needs. SortedUK guide.
- Carer's Allowance £4,331/yr — for anyone caring 35+ hours/week. SortedUK guide.
- Disabled Facilities Grant up to £30,000 — for home adaptations. SortedUK guide.
- Council Tax Reduction — if household income is low. Different from SMI disregard; can stack with it. SortedUK guide.
- Pension Credit if over State Pension age + low income — unlocks Winter Fuel Payment cascade. SortedUK guide.
- NHS Continuing Healthcare if care needs are primarily health-related (full NHS funding). SortedUK guide.
- Blue Badge — free parking + free disabled access in many councils. Free or small council fee.
- VAT relief on disability equipment — zero VAT on equipment for disabled use. Ask the supplier.
- Free TV Licence at 75+ — if they have Pension Credit Guarantee Credit.
Free UK support
- Alzheimer's Society Dementia Connect — 0333 150 3456 (free, Mon-Fri 9am-8pm, Sat-Sun 10am-4pm). Comprehensive UK dementia support.
- Age UK Advice — 0800 678 1602 (free, Mon-Fri 8am-7pm). Helps with SMI disregard applications.
- Mencap — 0808 808 1111. Learning disability support + Council Tax help.
- Carers UK Helpline — 0808 808 7777. Free advice for family carers.
- Citizens Advice — 0800 144 8848. Free benefits + Council Tax help.
- Stroke Association — 0303 3033 100.
- MS Society — 0808 800 8000.
- Parkinson's UK — 0808 800 0303.