Thanks every body for your answers
So its not so a profitable business, they depend on many daily movements to do a 10GBP profit (only a figure) and how people buy tickets, if the aircraft is only 1/2 full, no luggage extra cost, no internet banners, nobody use onboard catering and so. They depend on a hughe number of variables to reduce ticket price. What will happen if one of these variables fails? strikes, no cleaning the aircraft, delays. in 10 days they are off the business if this happens because they would not be able to support such looses.
Its not a good business, to much money to invest for so low profit.Selling drinks is much more profitable.