Severe Mental Impairment Council Tax Discount 2026 — SMI Disregard Explained

Who Qualifies for the SMI Disregard?

To be disregarded as severely mentally impaired, a person must satisfy both of the following conditions simultaneously (LGFA 1992, Schedule 1, para 2):

1. A registered medical practitioner (usually a GP) certifies a 'severe impairment of intelligence and social functioning which appears to be permanent, resulting from a condition such as dementia'. The word permanent is important — the GP is certifying that the condition is not expected to substantially improve.
2. The person is entitled to at least one qualifying benefit. These include: Personal Independence Payment (daily living component), Attendance Allowance, Disability Living Allowance (mid or high-rate care), Employment and Support Allowance, Universal Credit (limited capability for work), Incapacity Benefit, Severe Disablement Allowance, or the disability premium in Income Support.

Moderate cognitive decline, mild dementia, or mental-health conditions that do not meet the permanent severe impairment threshold do not qualify — even if they significantly affect daily life. The qualifying benefit requirement also means that a person who would qualify medically but has never claimed any benefit will generally be refused by the council. If that is the situation, help the person claim their underlying benefit entitlement first, then apply for the SMI disregard.

The person with SMI must be a resident in the property — they do not need to be the person named on the council tax bill.

How the Discount Is Calculated

Once the SMI person is disregarded, the council recounts the number of adult residents as if that person were not there. The discount level depends on the resulting count:

Source: GOV.UK — Council Tax: who has to pay and LGFA 1992, Schedule 1.

Common Qualifying Diagnoses

The following conditions are the most frequently certified as meeting the severe mental impairment threshold. Note that the diagnosis must be at the severe end of the condition — moderate impairment does not qualify:

• •Alzheimer's disease — The most common basis for SMI certification. Typically certified at moderate-to-severe stage.
• •Other dementias — Vascular dementia, Lewy-body dementia, and frontotemporal dementia, all at severe stage.
• •Parkinson's-related dementia — Parkinson's disease itself does not usually qualify — but advanced Parkinson's with severe cognitive impairment does.
• •Huntington's disease — Progressive neurological condition; typically qualifies once severe cognitive decline is established.
• •Severe learning disability — Congenital or acquired; must be documented as 'severe' in medical records.
• •Post-stroke severe cognitive impairment — Qualifying where a stroke has caused permanent severe impairment of intelligence and social functioning.
• •Severe traumatic brain injury — Where the injury has caused permanent severe cognitive impairment certified by a specialist.

Refer to the Alzheimer's Society council tax discount guide and MoneySavingExpert's SMI guide for practical claim templates and worked examples.

How to Apply

The SMI disregard is never applied automatically — you must apply to your billing council. The process has three steps:

1. Download or request the SMI disregard application form from your local council's website (search '[your council name] severe mental impairment council tax').
2. Ask the person's GP to complete the medical certificate section of the form, or provide a separate letter. The BMA confirms GPs must not charge a fee for this certificate.
3. Attach a copy of the qualifying benefit award letter — typically a DWP decision letter for PIP, Attendance Allowance, or ESA. Submit all three documents together.

When submitting, explicitly request backdating to the earlier of the date of medical diagnosis or the qualifying benefit award start date. Put this request in writing — email is fine and creates a useful record. See Citizens Advice — Council Tax for further guidance.

Common Pitfalls — Why This Discount Is Under-Claimed

The SMI disregard is estimated to be significantly under-claimed across England and Wales. Families miss it for several reasons:

• !Councils do not proactively notify. Unlike the single-person discount, councils do not flag the SMI disregard to households where it might apply. If a care agency or social worker does not mention it, most families never hear about it.
• !Families avoid the 'label'. Some families decline to apply because they are uncomfortable having a parent or relative formally certified as severely mentally impaired. The council never publishes or shares the diagnosis — it is administrative only.
• !The bill-payer assumes they must be the SMI person. Wrong. The SMI person simply needs to live in the property as a resident. The person named on the council tax bill can be anyone in the household.
• !People miss the backdating window. Councils will often only mention 'from today'. If you do not actively request backdating in writing, you may lose years of refund. Always ask in writing, citing the LGFA 1992 and providing evidence of the original diagnosis date and benefit award date.
• !Qualifying benefit not yet in place. Medical certification alone is insufficient. If the SMI person is not yet receiving a qualifying benefit, focus first on securing that entitlement — then the SMI disregard can be backdated to align with it.

Frequently Asked Questions

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