In order to reduce the number of cars on the roads and reduce pollution levels, among other alternatives the local councils try to encourage travellers to leave the car and use the bus. The only way this is going to work is if the bus fares are low and the bus service frequency is high.
For quite some time there has been a reduced fare scheme in place with a maximum single fare of £2 and a Day Saver ticket at £4.50. Unfortunately the bus providers have not supported this by providing more frequent services but have instead reduced bus frequencies.