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Carer reviewing council tax documents with an elderly family member at a kitchen table.

Severe Mental Impairment Council Tax Exemption: The Reduction Most People Never Claim

Written by Jess Gambo on . Posted in Council Tax, General News.

One of the most under-claimed council tax reliefs in England and Wales is the severe mental impairment (SMI) disregard. It is estimated that tens of thousands of households qualify but have never claimed. For a household with one qualifying adult and one other resident, the discount is 25 per cent. If both residents qualify, the property can be entirely exempt from council tax. Yet awareness of this relief remains extremely low.

What Is Severe Mental Impairment?

For council tax purposes, a person has a severe mental impairment if they have a severe impairment of intelligence and social functioning resulting from a condition that causes that impairment to be permanent. The condition must be one that has resulted, or is likely to result, in a severe impairment of both intelligence and social functioning.

Conditions that frequently qualify include:

  • Dementia (including Alzheimer’s disease and vascular dementia)
  • Severe stroke affecting cognitive function
  • Parkinson’s disease with significant cognitive impairment
  • Multiple sclerosis with severe cognitive effects
  • Brain injury causing permanent cognitive impairment
  • Huntington’s disease
  • Creutzfeldt-Jakob disease
  • Severe learning disability present since birth or caused by brain injury

A diagnosis alone is not sufficient. The key is whether the condition causes a severe and permanent impairment of both intelligence and social functioning. In practice, many people with moderate to severe dementia or brain injury qualify even if they have not specifically been told about this relief.

What Evidence Is Required?

To claim the SMI disregard, two conditions must be met:

  1. Medical certification: A registered medical practitioner (the person’s GP or specialist) must certify in writing that the person has a severe mental impairment as defined above.
  2. Benefit entitlement: The person must be entitled to at least one of a list of specified benefits. These include:
  • Incapacity Benefit
  • Severe Disablement Allowance
  • Disability Living Allowance (care or mobility component)
  • Personal Independence Payment (daily living component)
  • Employment and Support Allowance
  • Universal Credit (including a disability element)
  • Attendance Allowance
  • Constant Attendance Allowance
  • Disability Working Allowance
  • Income Support (in some circumstances)
  • Unemployability Supplement

Both conditions — the medical certificate and the benefit entitlement — must be satisfied. However, for an older person with dementia who receives Attendance Allowance, both conditions are typically straightforward to demonstrate.

How Does the Discount Work?

A person with a severe mental impairment is “disregarded” for council tax purposes — meaning they are not counted as an adult when calculating how many adults are liable for the bill.

The effect depends on how many adults live in the household:

  • Two adults, one with SMI: The person with SMI is disregarded, so the other adult is treated as the sole resident. The household receives a 25 per cent single person discount.
  • Two adults, both with SMI: Both adults are disregarded. The property is entirely exempt from council tax — a 100 per cent reduction.
  • One adult with SMI living alone: They are disregarded. The property becomes exempt — 100 per cent reduction.
  • Three or more adults, one with SMI: The person with SMI is disregarded, reducing the effective adult count by one. This may or may not affect the discount depending on the remaining count.

For a property in council tax Band D — close to the national average — a full exemption can mean saving more than £2,000 per year. Even the 25 per cent single person discount typically saves £400 to £600 per year.

How to Apply

  1. Speak to the GP or specialist: Ask them to provide a letter or complete the council’s medical certificate form confirming the diagnosis and that in their view it causes severe mental impairment as defined for council tax purposes. Most GPs are familiar with this — it is a standard letter, though some charge a small administration fee.
  2. Gather evidence of benefit entitlement: A recent DWP letter confirming the relevant benefit is usually sufficient.
  3. Contact your local council: Download the SMI disregard application form from your council’s website (search for “severe mental impairment council tax” on their site). Submit the completed form, medical certificate, and benefit evidence.
  4. Ask about backdating: Once approved, councils are generally required to backdate the discount to the date the qualifying conditions were first met. For a person who has had dementia for several years, backdated council tax reduction can result in a significant refund.

Can You Backdate the Claim?

Yes. Unlike some other council tax reliefs, the SMI disregard should be backdated to the date the person first qualified — provided you can demonstrate when both conditions (SMI and benefit entitlement) were met. If a person has been living with dementia and claiming Attendance Allowance for three years, the disregard should in principle be applied from three years ago, generating a significant refund or credit.

In practice, the council will ask for evidence of when the qualifying conditions started. The GP letter and DWP benefit records are the key documents. Some councils are more forthcoming than others about backdating — if yours is reluctant, make a formal written request and, if refused, consider a formal appeal or complaint.

Councils Are Not Required to Tell You

This is perhaps the most significant reason so many households miss this relief. Councils are not legally required to proactively inform residents about the SMI disregard. They are required to grant it when applied for correctly, but there is no duty to identify eligible households and contact them. The responsibility to apply sits with the household.

This is why the relief remains so widely unclaimed. Families caring for a relative with dementia are often focused entirely on care and health matters, and council tax discounts are simply not on their radar.

Getting Help

Council Tax Advisors can help you identify whether a household member qualifies for the SMI disregard, what evidence to gather, and how to submit the application and chase backdating. Contact us for free, specialist guidance.

Summary

  1. The SMI disregard can reduce council tax by 25 per cent or 100 per cent depending on household composition
  2. It applies to people with permanent severe impairment of intelligence and social functioning — including dementia, severe stroke, and brain injury
  3. Two conditions must be met: a medical certificate and entitlement to a specified qualifying benefit
  4. Backdating is available to when the conditions were first met — potentially generating significant refunds
  5. Councils are not required to proactively tell you — you must apply
  6. Free help is available from Council Tax Advisors

Disclaimer: This article is for general information only and does not constitute legal or financial advice. Qualifying conditions and rules may vary. Seek independent advice for your specific circumstances.