O2 launched its Green First eco-rating system this week in conjunction with sustainability advisers Forum for the Future. But one handset was notably absent from the listings - the Apple iPhone.Why no iPhone? Well, Apple claims it offers enough eco-related information via its own website, but so do other companies, like Nokia for example, which is taking part in the scheme. Greenpeace, for one, is obviously disappointed with Apple's lack of participation.Speaking to The Guardian, Gary Cook, IT sector analyst for Greenpeace International said: 'Transparency is always an issue for consumer electronics companies, who claim that providing too much information gives away competitive advantage. But consumers also deserve to know the full story. While Apple has recently made important strides in eliminating toxic chemicals from its products and the reporting of their environmental footprint, it still lags behind others in transparency.'Apple has been a vocal critic of Apple in the past, but has also praised Steve Jobs for his decision to phase out the use of brominated flame retardants and PVC in the manufacture of the company's products. However, it's decision to avoid the Green First ratings does cast a shadow over the company which could hit the company financially. According to O2, 11.5% of people it surveyed said sustainability had a 'strong influence' on which model they would buy.So what is the greenest handset? The Sony Ericsson Elm. Although that's somewhat tempered by a fairly lacklustre set of features and performance. You can't have everything it seems.