Do parents have the right to change a stinking nappy at a restaurant table? You might assume, as I did, the correct answer is, hell no. Yet reading a recent online debate I was startled by how many disagreed. That raising children is an arduous, stressful self-sacrifice, they reasoned, entitles parents to commit this disgusting, selfish act.

Believing that because you are a “good” person you have permission to do a bad thing is what psychologists call moral licence. It is epidemic in modern parenting: “That I am a noble nurturer of tiny infants entitles me to drive this 4x4.” When my elderly folks once parked in a supermarket parent-and-child space because all the disabled bays were full, they returned to find — despite the