£400 works out to $673 USD and based on that budget, you would be hard pressed to find a laptop with a 1080p screen and that is with integrated graphics. A dedicated graphics card / chip would mean a more expensive laptop.
£400 generally means a 15.6" laptop with either a Core i3 or Core i5 CPU and 1366x768 resolution screen with integrated graphics. Perhaps look on ebay or other sites in the UK that sells refurbished laptops.