Of all the activities your pupils could get up to this Christmas, carol singing is probably one of the least offensive. But that’s not necessarily what residents in Preston, Lancashire, think.

Police and Neighbourhood Watch organisers have produced official notices that say: “Sorry no carol singers, I won’t open my door to you.”

Nervous residents can put the yellow postcard-sized sign in their window to deter the singing cherubs.

“It is a terrible state of affairs that people are terrified of answering their doors,” laments Father Timothy Lipscomb, the local vicar.

But Chief Inspector Richard Robertshaw of Lancashire Police rejected accusations of a “bah-humbug” approach.

“Singing Christmas carols is a wonderful tradition that we encourage as long as children are considerate,” he says. However, some people are uncomfortable with groups on their doorsteps, he adds.

If any genuine miscreants obey the small signs, Santa has promised to eat his hat.