There must have been gnashing of teeth and the rending of heavily discounted garments in the marketing departments of Marks & Spencer, House of Fraser et al, when they realised that their commercial rival had been granted a three-hour advertisement on the BBC, but then there has always been something about John Lewis that seems to elevate it above the ruck and maul of the high street. What that something was – and whether or not it was purely mythical – was the subject of Liz Allen’s ultimately interesting documentary foray behind the façade of Middle England’s favourite department store. En route, you have to say, John Lewis got the most almighty plug at the licence fee-payers’ expense. It gave a whole new meaning to the store’s famous slogan, “Never knowingly undersold”.