The standard size for UK Double mattress is 135x 190 cm / 4 ft 6 in x 6ft 3in. However you can also buy a smaller Double mattress, 120x 190 cm / 4 ft x 6ft 3in, so check the size carefully. There are six main types of mattresses; a memory foam mattress, pocket spring, open coil mattress, latex, foam and continuous coil mattress. Many people visit a showroom to try out the Double mattress and then search for a good price online. This site has discounts and competitive prices from top retailers including coopbedshop.co.uk, John Lewis and Tesco. Popular brands are Dreamland, Silentnight and Sealy.