The minimum payment structure
Typical minimum payments are the greater of: 1-3% of the balance, £5-£25 minimum floor amount, or interest plus fees for the period.
The specific formula varies by card and by regulator requirements. Since 2011, minimums have had to at least cover interest, fees and 1% of the balance.
The math of minimum-only payments
A £3,000 balance at 25% APR paying just the 3% minimum: takes about 24 years to clear and costs about £4,700 in interest — 1.5 times the original balance.
The same balance paying £200/month clears in about 19 months at £3,750 total — over £1,000 saved compared to minimum-only.
This is why minimum-only payments are one of the worst ways to manage credit card debt.
The persistent debt rule addresses this
The FCA persistent debt rules (see the persistent debt notice FAQ) target exactly this problem. Cardholders in persistent debt receive escalating notices from month 18, 27 and 36.
The rules are designed to protect people from staying trapped in minimum-only situations indefinitely.
Better strategies
Pay the largest amount you can afford each month, not just the minimum.
Focus extra payments on the highest-interest card first (avalanche method) or the smallest balance first (snowball method).
For balances you cannot realistically clear, consider balance transfer or a formal debt solution.