Online retail guys Smartfonestore have a bunch of iPhone 4 refurbs for sale, from £295 for the 16GB model. The 32GB will set you back £345, or you can grab either in white for an extra fiver.
There’s a choice of network, namely O2, Vodafone, Orange or Three, and the iPhone 4 refurb comes locked, fully tested, and with a 60-day warranty.
Apple USB cable included.
(Thanks to r3tract @ HUKD)