Britain: the minimum payment is a rule, not an issuer's choice
Britain is one of the few markets where the minimum payment is written into regulation rather than left to the card company. FCA rule CONC 6.7.5, which applies to card and store-card agreements made on or after 1 April 2011, requires the minimum to repay the interest, fees and charges applied that month plus 1% of the amount outstanding, so a British minimum is 1% of the balance added on top of the interest, with a flat floor of about £5 on small balances.
That 1% sounds gentler than the 3% or 5% common elsewhere in Europe, but it is not comparable: because the interest is charged separately, the whole 1% comes off the debt. A 3% minimum with the interest taken out of it repays less principal than Britain's 1% once the rate passes about 24%.
The rule that actually shortens British card debt is a different one. Under the FCA's persistent-debt rules, in force since 2018, an issuer must intervene when a customer has paid more in interest, fees and charges than principal over 18 months, and again at 27 and 36 months, ending in an offer to clear the balance over what the FCA's guidance treats as a reasonable period, normally three to four years. Setting the calculator to minimums and reading the answer in decades is therefore a description of the maths, not of what your issuer is allowed to let happen.
Britain has no interest-rate cap on credit cards, so nothing limits the APR itself.