British cellular carrier O2 has overhauled its iPhone plans in a likely effort to make the device more appealing to a broader customer base.

In addition to currently available plans, O2 has introduced a new heavy usage plan for customers who may use their iPhones more frequently. Also, customers of one of its plans will be moved down to a less expensive tier.

Currently, the company offers plans at £35, £45, and £55 per month. O2 will phase out the £55 tier and move its customers down to the £45 monthly plan. A high-end £75 tier will also be added.

Those with the cheapest plan will see their monthly free minute allowance increased threefold from 200 to 600, and their free text limit more than doubled. The new £45 plan includes the same amount of minutes and texts as the old plan.

If customers still need more minutes and texts, the new £75 tier includes 3,000 free minutes and 500 texts per month. No changes will be made to the data, which is unlimited, and customers will still be able to access Wi-Fi hotspots through The Cloud at no additional charge.

While it appears that the changes may have a lot to do with seemingly lackluster sales of the device in the UK -- it is said to be missing sales targets -- it also is part of a broader tariff reorganization taking place across the service.

"This industry is infamous for confusing consumers with the number and complexity of tariffs," marketing chief Sally Cowdry said. "We've listened to what our customers want and acted, offering simple but competitive tariffs across all our handset range."

O2 maintains that the iPhone is its fastest selling device to date, and sources say that the handset is only narrowly missing targets -- selling 190,000 units in the first eight weeks of release versus initial company projections of 200,000 units.