According to this article at the BBC, a network of 250 digital screens in 150 cinemas across the country is being planned. Each film is losslessly compressed from 1 Terabyte down to 100 Gigabytes and encrypted onto a portable hard disk drive with a key unique to each cinema, which is then delivered to the cinema.
Each cinema projector will be capable of showing films at resolutions of 2048 x 1080 pixels. "The key benefit is the distribution and screening of documentaries, British and foreign language films, as making a digital copy is considerably cheaper than spending over ?1500 pounds to make a copy of a single film". Other benefits include better picture quality and the ability to show more films each day."