Taken from Fire Service info
Traffic Signs Regulations and General Directions 1994
Regulation 33(1)(b). Under this regulation a red traffic light may be treated as a 'Give Way' sign when observance would hinder the purpose for which the vehicle is being used and provided that no danger is caused to other road users and that the driver of another vehicle is not caused to change speed or course to avoid an accident. Taking advantage of this exemption is likely to bring a fire service vehicle into conflict with other road users including pedestrians, and it will almost always be necessary to reduce speed and use warning horns or bells as well as warning lights while doing so.
Similar story from 2008
http://www.dailyrecord.co.uk/news/sc...6908-20686060/