The operator, owned by Spain Telefonica, said customers would be able to pay for their new devices in monthly increments for any period between three and 36 months, all with no interest charged, as well as choosing an airtime plan.

Chief Executive Mark Evans said on Wednesday: "Our custom plans put power back in the hands of the consumers who don't want to be tied down by rigid contracts especially at a time when certainty and transparency are at a premium in today's economic environment."

O2, the second largest British operator after BT, said the "Custom Plans" built on the tariffs it introduced in 2013 that separate the cost of airtime and the cost of paying for the phone, and the change it made last year that allows customers to increase or decrease their airtime each month depending on their data needs.

(Reporting by Paul Sandle; editing by David Evans)

Stocks treated in this article : Telefonica, BT Group