Large numbers of folk tales, not just Rumpelstiltskin, attest to the primitive power invested in a man's name. There is a terrific power and intimacy involved in the act of naming. Not so very long ago, it was quite a rare thing for most people to use forenames routinely. Respectable old ladies could know each other for years without venturing onto first-name terms; both my grandmothers would have died rather than call their best friends anything other than "Mrs Jones" or "Mrs Smith".

There is an unaccustomed acuteness, then, in the Labour Party's reported diktat over Mr Boris Johnson. Tessa Jowell is said to have ordered an emergency "Boris Box" in Labour's London mayoral campaign headquarters. Every time anyone refers to Johnson as "Boris", they will have to cough up a fiver. The way everyone always talks about "Boris" is, they fear, contributing to a likeable and familiar image, which is going to be hard to beat.

Some people like to pretend that the current mayor is known, too, to all and sundry as "Ken". I doubt it very much. I've never heard anyone refer to him as anything but "Ken Livingstone" or even "Livingstone". One of the surprising developments of Boris Johnson's generally interesting career has been that people who don't know him at all have started calling him "Boris". One conversation about five years ago took on an unnecessarily confusing aspect, as I assumed that the person I was talking to had met Boris; he, on the other hand, assumed that I hadn't.

All this first-naming conflates a modern and a historic habit. The modern one, much beloved of newspapers, is those modern celebrities who are distinguished by one name alone – Elton, Madonna, Kylie, Beyoncé. Who is Beyoncé? No idea.

I suspect, however, that the origins of all that Boris-ing lie in a more historic habit. Both the Conservative Party and the world of letters to which Mr Johnson belong share the same manners in their private life. The most insignificant of Conservative MPs and the biggest of parliamentary beasts will, in a pretence at equality, use each other's forenames in conversation and when referring to each other. Lady Thatcher's habit of talking about "Winston" is always derided, but that was the habit she developed as a young MP. It would have been utterly infra dig to have talked about "Sir Winston" or "Churchill" as a young MP in the early 1960s, and she has maintained the habit.

Similarly, writers and journalists have always called each other by their first name, if they have met even once. There is an egalitarianism in manners in both of Boris's fields of operation, which has spread into the wider population very easily. It doesn't spread for everyone; but for someone of the happy charm and personal appeal of Boris, it has spread.

In the case of the Labour Party, alas, there is nothing by way of charm to spread. If there is nobody in the Cabinet whom one can imagine being called by their forenames, that might be because they don't have the same manners. Even the Prime Minister refers unfailingly to his deputy as "Harriet ... Harman" with cold distaste. It has always been so. I once shared a canteen table with the late John Smith and was transfixed by the venom with which he referred to "Cook ... Blair ... Brown..."

Tessa Jowell is right that all that Borisieren reflects a sense of warmth and likeability. She is wrong, however, to think there is anything she can do about it. As it happens, although "everyone" is said to call Boris Boris, that isn't quite true. His own family don't. They call him Al.

Hats off to the ladies of Aintree

How transfixing were the photographs of the ladies of Liverpool, attending the Grand National in outfits individually unremarkable, but in combination positively surreal? One photograph I saw displayed a lady in a full-length ball gown, her friend in bright yellow hotpants and a third in white flares.

The fact is that we don't, any longer, have a range of accepted outfits for different social occasions in the way that a more leisured society had. We have, basically, Work (drab), Weekend (elasticated waistband), and Getting Dressed Up. The latter may mean anything from ballgown to gold lamé thong. In theory, I like this new liberation, but nobody can deny that some people ought never to be allowed into Top Shop on their own.

* Private Eye published rather a brutal parody of my new novel, The Northern Clemency, last week, which I have to say I very much enjoyed. "Yes, there are new people moving in at No 21," she heard Mrs Crasher saying. "The Teigh-Deighams, I think they're called..." I don't know why it is, but to be parodied, however viciously, provides a pleasure in a way no review ever could, good or bad.

Not all parodies are to the point – there's that man in The Guardian who has never noticed that good novelists don't vary their verbs of speech – but when they notice something, as the best parodists infallibly do, it must give pleasure even to the victim. For instance, Craig Brown, surely the very best of contemporary parodists, reveals a covert love for his victims' prose, even at their most self-regarding. There are not many readers who pay as close attention to one's most ambitious effects, as well as one's habitual blunders, as the parodist. It is nice to know, all in all, that someone has been paying attention.