Ofcom (the Office of Communications, an independent organisation that regulates the UK's telecommunications and wireless communications sectors) has released 3G coverage maps by mobile operator that don't look so good for UK exclusive Apple iPhone and Palm Pre carrier O2.

O2 this week announced an exclusive agreement to sell the 3G Palm Pre phone in the UK. It is already the UK exclusive carrier for the Apple iPhone 3G and iPhone 3GS.

The carriers compared by Ofcom include 3, O2, Orange, T-Mobile and Vodafone.

The examples shown below are O2 and Orange. The shaded areas on the maps indicate areas where customers have the possibility of making and receiving a call outside over a 3G network (but with no guarantee of being able to do so).

Ofcom 3G coverage maps

Download the Ofcom maps here.

All operators produce their own coverage indicators on their websites, which are likely to provide more reliable guidance to network availability in any given area, says Ofcom.

The accuracy and detail of the Ofcom maps are not to the same level as the mobile operators publish, admits the regulator.

Prepared in January 2009, they represent the area where mobile operators are assessed whether they meet a minimum coverage threshold set by Ofcom.

They do not indicate areas where customers are able to access higher data rate services.

Ofcom's maps show UK-wide general coverage and are not suitable for zooming in to see specific locations (eg. a particular house or street).

Also they are not suitable for assessing the quality or depth of coverage within the indicated areas (eg. different operators may be able to offer better or worse data rate services or support a smaller or greater number of users).