Heathfield is right, but there is also a product on the market for pipes. Electrical may be better, I've just had a search for trunking for pipes and found it very expensive. Measure what size would fit your pipes, I think go to an electrical wholesaler and ask for MT5 this should do but check(not self adhesive it's better to screw it to the wall). When you have finished fixing it, cover with lining wallpaper and run decorators caulk down the sides to hide any gaps and then paint over. You should pay around a tenner for a 3 meter lenth, I think B&Q only do 2M lenths which means you will have a joint, if you resort to joining 2 lenths then make sure you put the long cover on the short lenth so that it overlaps and the joint is staggered.
www.electricalwholesalesupplies.co.uk/F02/PPF02P05.php?t_mode=cat&t_id=80