SMI council tax disregard: back-claim up to 6 years

What the disregard does

Schedule 1 to the Local Government Finance Act 1992 sets out the list of people who are disregarded for the purpose of counting adult residents for council tax. Among the disregarded categories is a person who is severely mentally impaired. The disregard treats the person as if they were not a resident, which can change the household's council tax position significantly.

The disregard does not change the band or the gross bill. It changes the count of adult residents. So a household with two adults, one of whom has SMI, is treated as a single-occupant household and qualifies for the 25 per cent single person discount. A household where the only adult resident has SMI is treated as having no adult residents and is exempt under Class U of the Council Tax (Exempt Dwellings) Order 1992.

The two-part test: medical and benefit

To qualify, the person has to satisfy two distinct tests. The first is medical: a registered medical practitioner has to certify that the person has a permanent severe impairment of intelligence and social functioning. The certificate is normally provided by the GP, but a consultant geriatrician, neurologist, or psychiatrist can also provide it. There is no standard form; the GP writes a short letter confirming the SMI status with the date of onset where known.

The second test is benefit-related: the person has to be entitled to one of the qualifying benefits listed in the Council Tax (Discount Disregards) Order 1992. The full list (as updated by various amendment orders) includes:

• Attendance Allowance (either rate)
• Personal Independence Payment, daily living component (either rate)
• Disability Living Allowance, middle or higher rate care component
• Severe Disablement Allowance
• Constant Attendance Allowance (Industrial Injuries scheme)
• Unemployability supplement or unemployability allowance
• Income Support including a disability premium because of incapacity for work
• Increase in the rate of Disablement Pension
• Universal Credit including the element for limited capability for work or work-related activity
• Armed Forces Independence Payment
• Incapacity Benefit at the long-term rate
• Employment and Support Allowance

Both tests have to be satisfied. A person with the medical impairment but without an entitlement to a qualifying benefit does not qualify. A person with a qualifying benefit but without the medical certification does not qualify. Most people with a permanent severe cognitive impairment are entitled to Attendance Allowance or PIP daily living, so the benefit test is normally satisfiable if the medical test is.

The most common qualifying conditions

In practice the SMI disregard most often applies to people with:

• Dementia (Alzheimer's, vascular, frontotemporal, dementia with Lewy bodies). Often qualifies from the moderate stage onwards.
• Severe learning disability. Qualifies from birth or from the diagnosis date depending on the underlying condition.
• Stroke that has caused permanent cognitive impairment. Qualifies from the date the impairment is confirmed as permanent (normally 6 to 12 months post-stroke).
• Severe brain injury. Qualifies from the date the impairment is confirmed as permanent.
• Parkinson's disease at the cognitive-impairment stage. Qualifies when the cognitive symptoms become substantial.
• Severe multiple sclerosis with cognitive involvement. Qualifies when the cognitive impairment becomes substantial.
• Huntington's disease at the symptomatic stage.

The disregard is conditional on the impairment being severe and permanent. A temporary cognitive impairment (post-operative confusion, treatable depression, recoverable substance-use confusion) does not qualify. The medical practitioner's certificate is the determinative document; councils generally accept the medical opinion without further inquiry.

How much the disregard saves

On a household with one adult resident with SMI and one other adult:

• Band D national average £2,392 reduced by 25 per cent to £1,794 a year
• Annual saving: £598
• 6-year back-claim: approximately £3,500 at recent national averages

On a household where the only adult resident has SMI (the property is exempt under Class U):

• Bill reduced to £0
• Annual saving: full bill amount (£2,392 at Band D national average)
• 6-year back-claim: approximately £14,000 at recent national averages

The amounts scale by band. On a Band H property the single-occupant saving is £1,196 per year and the exemption saving is £4,784 per year. Back-claims at Band H can therefore be £7,000 to £28,000.

Step-by-step: how to apply

Step 1: Get the medical certificate

Contact the GP and ask for a council tax SMI certificate. Most surgeries are familiar with the form and can provide it within 1 to 2 weeks. There may be a small administrative fee (typically £20 to £40), which most councils reimburse on successful application. The GP can sometimes attach a date of onset based on the medical records, which is useful for the back-claim.

Step 2: Confirm the qualifying benefit

If the person already receives Attendance Allowance, PIP daily living, or another qualifying benefit, you can use the existing award letter. If not, apply for the relevant benefit first; the SMI disregard cannot be granted without an entitlement to a qualifying benefit. Attendance Allowance is the most common entry point for older people; applications are made via gov.uk/attendance-allowance.

Step 3: Submit the SMI application to the council

Most councils have a dedicated SMI application form on their website. Submit the medical certificate and the qualifying benefit award letter together with the form. For a back-claim, also provide:

• The date of onset of the SMI (from the medical certificate or family knowledge)
• The date the qualifying benefit was first awarded
• Any historical evidence of the person's impairment from before the formal diagnosis

The earlier of the two dates (SMI onset or benefit award) is normally the start date for the back-claim, subject to the 6-year limitation period.

Step 4: Wait for the decision

Most councils process SMI applications within 4 to 8 weeks. The processing time is longer than for the single person discount because of the medical and benefit evidence to review. Once approved, the discount is applied retrospectively to the start date and any over-paid council tax is refunded.

If the claim is disputed

Councils occasionally dispute SMI back-claims, particularly where the medical certificate is unclear about the date of onset or where the qualifying benefit was awarded after the SMI date. The dispute can be escalated to the Valuation Tribunal under section 16 of the LGFA 1992. The tribunal hearings are informal and free; most disputes settle before the hearing once the council has reviewed the evidence again.

For complex cases (particularly with several different historical benefits or unclear medical records), Citizens Advice and the Alzheimer's Society both have specialist advisors who can help compile the evidence. The Alzheimer's Society in particular has run national awareness campaigns about the SMI disregard and has detailed guidance on its website.

Why this is so often missed

The SMI disregard is heavily under-claimed for a combination of reasons. The eligibility requires medical certification, which families often do not realise is available. The qualifying benefits list is long and unfamiliar. The disregard can apply alongside the single person discount in ways that are not obvious. Councils do not proactively flag the disregard to families even when the qualifying benefits are visible on the council's records.

A 2018 Money Saving Expert investigation found over 100,000 households nationally with a known SMI-qualifying condition but no SMI disregard claim. The aggregate over-payment was estimated at over £400 million. The picture has improved since 2018 with awareness campaigns, but the SMI disregard remains one of the most significantly under-claimed reliefs in the system. If you have a family member with dementia, severe learning disability, stroke aftermath or another qualifying condition, it is well worth investigating whether they qualify.

Related pages

See also how to claim the single person discount, how to apply for council tax reduction, and our discounts hub. For per-band cost see Band D cost 2026/27.