Letter: How drivers can switch off city-centre air pollution

Sir: As a coach driver I can offer a simple explanation of the behaviour referred to in Deborah Moggach's open letter to John Gummer (12 September). Coaches parked in Shaftesbury Avenue are usually waiting to pick up passengers after the theatre, by which time it becomes quite chilly. Coach interiors take an inordinately long time to warm up and the heating systems in most of them depend on having the engine running, both to provide heat and to pump it through the heating circuit.

Since coach drivers rely heavily on tips to augment their basic wages, the comfort of their passengers is of great importance to them. There is also a significant safety consideration, in that the windscreen of a cold coach would become misted-up as soon as the passengers embarked.

For these reasons, and despite my personal concern for the environment, it has always been my practice to run the engine of my coach for 20 minutes or so before the passengers embark.

Yours faithfully,

TERRY WARREN

Rustington, West Sussex

12 September