UK players used to top up casino accounts using phone bill deposits, often...

https://planetfitnessprices.com/how-mobile-casino-deposits-have-evolved-from-phone-bills-to-instant-transfers/

UK players used to top up casino accounts using phone bill deposits, often limited to around £30 per transaction. Now, Faster Payments and mobile wallets let you add funds quickly and securely, with minimum deposits as low as £10