I went to a local Tesco looking for the £45 mountain bike & after checking the details on the box I found I needed to 26" bike. This bike is currently £60 instore I had the last one from the shelf. Online it says original price was £120, but reduced to £100, so I think for £60 instore is a good deal, it did come to £58 something because of the VAT reduction. I'm not sure if the offer is nationwide or not but the store I got mine from was the Culverhouse Cross Tesco Extra. A description taken from Tesco.com:
This Vertigo Nordend men's bike comes in ys-728 black, and features a steel frame with 26" 26" x 1.95 wheels. This mountain bike has front disc brakes, and 18 Shimano gears. The Vertigo Nordend dual suspension bike is suitable for riders with an inside leg measurment of 27.5-35".