Primary government and regulator sources first
The ONS publishes the authoritative online retail share; UK Finance the authoritative payment-method splits. Where industry vendors publish competing figures, we prefer ONS and UK Finance.
Industry estimates are labelled
Where no official figure exists (cart abandonment, SCA drop-off), we cite the industry source by name and treat the number as directional, not authoritative.
Wallet definitions are explicit
“Mobile wallet” means an Apple Pay / Google Pay / Samsung Pay card-funded transaction. PayPal is reported separately even though some sources combine it.
Cross-border definition
Cardholder UK / merchant non-UK, by card-issuer perspective. Excludes UK cardholders abroad in person.