I noticed the pack of cereal had been chewed through this morning and there was evidence of mouse droppings on the worktop. What should I do?

You should contact us immediately. Mice have a very nasty habit of urinating wherever they go, they have very loose bladders. You and your family could quite easily suffer from the consequences of their visit. The diseases they carry could result in a very severe upset stomach. Throw the carton of cereal in the dustbin and thoroughly clean the worktop with bleach to remove any trace of urine. Put all cereal products in sealed containers.