Thousands of households across the UK are waking up to unexpected £100 fines from the NHS after unknowingly breaching exemption rules when switching from Tax Credits to Universal Credit.

Money-saving expert Martin Lewis revealed the surge in fines during a live broadcast, highlighting that many families are being penalised for rules they didn’t know had changed. The issue stems from a fundamental shift in how eligibility for free prescriptions and dental treatment is calculated under Universal Credit compared to the old Tax Credits system.

Under the previous Tax Credits system, households earning around £14,520 after tax could still qualify for free NHS prescriptions and dental treatment. However, under Universal Credit, the earnings threshold can drop as low as £5,220 or £11,220 depending on individual circumstances. This means families who previously qualified may no longer be entitled—even if their financial situation appears unchanged.

The discrepancy arises because Universal Credit assesses eligibility on a rolling monthly basis, meaning income changes can revoke entitlements unexpectedly. Many households only discover the rule change after visiting the dentist or pharmacy, where staff flag the incorrect exemption claim. Lewis warned that patients often tick the benefits exemption box automatically, assuming their previous entitlement still applied.

Official NHS data obtained through Freedom of Information requests reveals a 58% rise in dental penalty notices in 2024/25, with over 150,000 fines issued for incorrect claims. Prescription penalty notices increased by 17%, while incorrect benefits-based prescription claims surged by 632%. Many of those fined believed they were still eligible, often because they were receiving other benefits like Disability Living Allowance for a child.

One affected woman, who moved from Tax Credits to Universal Credit last year, described her shock when a £100 fine arrived weeks after a dental appointment. Despite her child receiving Disability Living Allowance, her claim was rejected on appeal. “I just hope other people don’t get a nasty surprise,” she said. Dental clinics, including Forever Dental and Skin, are urging patients to verify their eligibility before claiming free treatment, noting that Universal Credit rules are frequently misunderstood.

1. Check your status — Use the NHS eligibility checker or contact the NHS Business Services Authority to confirm your entitlement.
2. Review monthly — Universal Credit income assessments change frequently; recheck your eligibility if your earnings vary.
3. Appeal if necessary — If you receive an incorrect fine, challenge the decision through the NHS Business Services Authority within 28 days.

Lewis criticised the lack of clarity in NHS exemption forms, arguing that they fail to adequately explain the rule changes for those transitioning from Tax Credits. Many households are being penalised not through malice, but through a lack of awareness. The financial expert is calling for clearer guidance to prevent further families from falling into the costly trap.