Retailers are used to having to comply with all sorts of rules about age-restricted sales, but in the digital era retailers’ iPhone apps are, like films, rated according to suitability.

M&S’s app, released last week, has a 12-plus classification. The reason? “Infrequent/mild alcohol, tobacco, drug use or references to these.” M&S and ‘parental guidance’ is an incongruous association, but lots of retailers including Waitrose are rated the same.

Department store group Debenhams on the other hand has a 4-plus rating. Its Designers range is obviously regarded by Apple as child-friendly.