The county council, concerned about the decline in numbers, has prepared around 200 balls with penny-sized holes for the mice to nest in.

BBC: Harvest mice in Leicestershire get tennis ball homes

Commenting on the survey's findings, Dr Penny Woods, chief executive of the British Lung Foundation, said the significant decline in the numbers of people smoking in Britain over the last 40 years was "a testament to the effectiveness of combined legislation and awareness raising in tackling what is Britain's leading cause of preventable illness and premature death".

BBC: ONS survey: Smoking halves in 40 years