Sir – Re queries about the problem of horse droppings should horse carriages be introduced to Oxford.

We were in Engelberg, in Switzerland, this spring and admired the solution they found. Each horse has a shute attached to its backside through which the droppings fall into a container underneath the front of the carriage, which is presumably emptied at the end of each run.

The horses seemed perfectly content with this; the shute was well clear of their back legs and they were working quite contentedly on pretty slippery roads.

Dick Brown, Wantage