Orange has ended up bottom of a consumer satisfaction league of mobile phone companies.
Rival providers Tesco Mobile and Virgin Mobile were named the best phone companies in a survey of pre-pay and contract customers.
The 2008 UK Mobile Study found that 20 per cent of contract customers intended to switch provider, compared with 10 per cent of pre-pay customers.
Companies’ "green" credentials were increasingly important to customers, according to JD Power & Associates which carried out the research.
Caspar Tearle, director of service industries research at JD Power & Associates, said: "Being 'green’ is an increasingly important requirement of today’s mobile telephone service providers, and it will be interesting to track how customer expectations for greater environmental friendliness will shape the industry within the coming years."
The study was based on responses from 3,340 pre-pay and contract mobile phone customers throughout the UK during February.
Respondents were asked to rate their phone company on image, cost, call quality, promotions, handsets and customer service. Companies were then given an overall score.