Well Phones 4U have launched a MVNO called 'LIFE Mobile' on EE's network and their press release states that they plan to launch 4G services on that 'later in the year'
http://www.phones4u.co.uk/media/pres...h-life-mobile/. With Virgin already running on EE's network I would think that they would start to be able to offer 4G around the same time as LIFE.