For those of you going on holiday in the next few weeks, spare a thought for the people who usually deliver your post: a break in routine can cause havoc. The Labour politician, Alan Johnson, who used to be a postman, recalls in his latest volume of memoirs, Please, Mr Postman, which has just been published in paperback, that a cancelled newspaper caused one of the most embarrassing moments of his postal career. His round in Buckinghamshire included two Daily Telegraph readers, an abbess and a reader who used his particular copy as a “Trojan horse” – tucked inside were the top shelf magazines the reader also ordered. One morning, Mr Johnson realised too late that he had delivered this paper to the abbess, who had cancelled hers because of a holiday. “I broke i