The £14.99 monthly charge for the service covers subscription and telephone costs, as well as unlimited free technical support.
To prevent oversubscription, the service is intially being offered to existing members. Flat Rate is made possible through FRIACO (Flat Rate Internet Access Call Origination), BT's wholesale flat-rate tariff.
BT was ordered to offer the tariff in June by the UK telecom-industry regulator, Oftel, following a ruling that SurfTime – its retail flat-rate package – was uncompetitive.
AOL is initially offering Flat Rate to its longest-serving customers. The service will be offered to the rest of the UK after it has been made available to all existing customers.
Until then, customers can sign-up for a free one-month trial with no subscription fee and 24 hours’ free access.
After the trial, users will be swtiched to AOL's standard tariff of £9.99 per month plus 1p per minute. These customers will have the opportunity to join Flat Rate when network capacity allows.
Managing director of AOL UK, Karen Thomson, said: “Our unmetered price plan is a watershed event for consumers that will transform the interactive medium into a true mass-market phenomenon in the UK.”