FinanceFlow lesson · life-of-a-card-payment · Sources: PSR (IFR caps) · FCA & HM Treasury (contactless £100, 2021; rule change 19 Mar 2026) · UK Finance (94.6% contactless 2024; Section 75 & chargeback) · BIS CPMI · Visa / Mastercard four-party model · Marqeta · Consumer Credit Act 1974 s.75. Some pence-level figures are illustrative.