Argos sells the Toshiba L870 laptop for £378.94, a price that includes 375 nectar points and delivery. Note that the product is refurbished but comes with a 12-month warranty.
Interestingly at this price you get a combination of big screen, powerful CPU, uncommonly high capacity and system memory. The L870 features a Core i3-2328 CPU from Intel, one that has two cores, is clocked at 2.2GHz and comes with 3MB cache.
The rest of the features consists of 8GB of RAM, a 1TB hard disk drive, a 17.3in display with a 1,600 x 900 pixels display, a DVD writer, an Intel integrated graphics unit, a card reader, three USB ports, Wi-Fi, Bluetooth, an Ethernet port, a webcam, Microsoft Windows 8, a HDMI connector, SRS Premium Sound HD system and as expected a dedicated numeric keypad.
The L870 has a battery life of around 3.5 hours which is fairly disappointing. A positive point though is that it weighs only 2.7Kg, which is roughly what you'd encounter for a laptop with a 15.6in display.
It is surprising that no manufacturer has come up with a 17in version of the Ultrabook (although this might be viewed as an oxymoron too far).