Not sure but this seems a good 18 month deal and includes both black and white versions with plenty of mins, texts, data.
Web 600 (18 month) 600 mins, 500 texts, Unlimited data.
13 months half price line rental by redemption, but what makes it easier is you can email them your bills to claim the cashback. Mobiles.co.uk is part of Carphone Warehouse. Also this link helps with the line rental cashback: http://forums.moneysavingexpert.com/showthread.php?t=1873989.
How to get this:
18 months @ £30 = £540
13 months half price brings it down to £345
less £50 Quidco = £295 or £16.38pm over 18 months (potentially!!)
direct link : http://www.mobiles.co.uk/t-mobile-white-htc-desire.html