Sir – Well done Stagecoach for the successful introduction of hybrid diesel-electric buses in Oxford.

On board, and slowing down at bus stops, then indeed there is the distinctive whirr of electric motors operating in reverse as generators. Hence all the energy due to the weight of the moving bus and passengers is converted to stored electric energy in the batteries, ready to restart the bus as it sets off again.

On conventional buses, all that energy would be simply lost through heat off the disk brakes.

The electrically-driven acceleration is impressive, much more akin to a sports car than a double-decker bus, so do hold tight if standing!

Human-induced climate change is a real risk and for very sound scientific reasons. Yet we often feel frustrated as to how we can “do our bit to help” to reduce emissions.

Anyone feeling that way should be greatly encouraged by making a test-ride up the Cowley Road on Stagecoach’s route one.

Dr Chris Huntingford Wallingford