A couple of months ago a friend asked if I'd write her a job reference. She is bright and witty and sophisticated and for about 20 years has held a succession of powerful jobs in television and newspapers.

Yet this latest position was rather different: she had applied to be a receptionist at a small office building in Mayfair. This struck me as an eccentric career choice for a clever woman on the cusp of 50, but I wrote out the reference and in due course she got the job.