So Hugh Grant has joined the Harbour Club, that fashionable fitness centre for off-duty rugby stars and resting princesses. Well, well. It's hard not to feel that some tremendous 24-carat super-scandal is in the offing - a feeling that grows even stronger when you hear that Leslie Grantham, once televisually renowned as Dirty Den, has also recently joined, as has Nick Mason, the rumpled car fanatic who occasionally plays drums with Pink Floyd. Will they, too, find themselves exchanging love tokens with the Princess of Wales? Will Mr Grantham put up with being called "Pootles", or some such emetic nickname? Will Mr Mason try to woo Diana by giving her Nautilus equipment a ferocious drubbing in strict 4/4 time? Will Hugh Grant offer her a lift?

The club has sent its members a little note, couched in foggy British legalese. The circular reads: "May we ask members to remind their guests that the privacy of members is of paramount importance and value to all members. For guests to divulge, into the public domain, information about members or their use of the club is a breach of the privilege of using the club, and is not appreciated by either the members or the managers of the club." And in English: "Stop tipping off the press, you bastards."

Cryptologists, cryptanalysts and cryptophiliac hangers-on from all over the metropolis piled into London's Travellers Club on Tuesday night for the launch of Robert Harris's novel Enigma, a thriller set in the Bletchley decoding works during the last war. It was the first big party of the autumn publishing season, so le tout Londres et sa femme showed up: John Mortimer, Cherie Booth, Robin Day, Angus Deayton, Lord Jenkins, Joan Bakewell, Jon Snow, Susan Crosland, Anthony Howard, Sebastian Faulks, various editors, diarists and a few (though you couldn't be absolutely sure) ex-Bletchley geniuses pullulated in the canape-free multitude.

Conversation - spectacularly unconnected to the subject of the book, as is the way with such gatherings - revolved around the tanned loveliness of back-from-the-grave Stephen Fry in his new lemon-curd hairdo, a weird rumour about the state of Prince Andrew's health, and the amount that Martin Amis is being paid to review books for the Sunday Times (pounds 6,000, since you ask, or pounds 4 a word). John Mortimer puzzled over a recent interview he gave to an Irish newspaper. When saucily asked by a bandage-skirted colleen if she could have his next baby, he gallantly replied, "I'm afraid I'm far too old"; but when the piece appeared in the paper his reply had mystifyingly changed to "I'm in Room 328 ...".

Enthusiasts for details of the real-life Enigma stuff swarmed around Margaret Macintyre, the saintly mother of this organ's craggy political editor, to ask for her memories of the code-crackers' HQ. The evening's booby prize, however, went to those who spent half an hour with a plausible gatecrasher from the Pall Mall pavement; when the club management tried to eject him, his extemporised memories of Alan Turing and Co had the assembled scribblers crying, "No, no, leave him alone, this is fascinating

Rock 'n' rollers who cannot live without those crucial bits of glamorous ephemera (who would rather Get the T-Shirt than Listen to the Music) should take themselves off to Christie's, the south Kensington auctioneers, where they're downloading a stack of "guitar and pop" collectables on the image- conscious faithful. Apart from the sequinned jackets (Jagger's, from the Steel Wheels tour, pounds 1,500) and other rag-trade impedimenta (Annie Lennox's Red Bra, pounds 250, Madonna's gold-studded Givenchy gloves, pounds 400) and the usual backstage hardware (like the Gibson Thinline on which Deep Purple's Ritchie Blackmore played "Smoke on the Water", pounds 5,000, bloody hell) there are a couple of frankly baffling items.

One, a document dated 21 November 1958, is - can you guess? Cliff Richard's recording contract? Jerry Lee Lewis's marriage certificate? - neither. It's an application form to take the art exam at Liverpool College of Art, duly filled in and signed by one JW Lennon. (It's going for pounds 1,200. Moral: why not keep those old Lloyds paying-in books, and one day they will keep you.)

The other, valued at pounds 400, is the official notebook of a German military cop who was on duty at the Berlin wall, Checkpoint Bravo, in 1967, who got a valuable endorsement from a chap not usually thought a fan of totalitarian regimes. "Be Groovy, Keep Kool," it reads chirpily, "the Best of Success to You, Jimi Hendrix."

Thanks to all the Promenaders who wrote in to explain what was going on down in the Albert Hall arena a couple of weeks ago, when I was startled to hear a section of the walkabout audience suddenly shouting in chorus at the orchestra. Were they chanting abuse? Were they attempting to sing a cappella? Well now I know.

Anybody with half a brain, I am told (Promenaders are a strikingly abusive bunch) knows that there's a tradition by which knots of Prommies call out questions and smart remarks, either to their confreres up in the gods (with the words, "Arena to Gallery

The night I went, Ms Gillian Grant from Sevenoaks tells me, they yelled "Do you rotate individually or ensemble?" at the strings and brass. Only a microscopic check through the programme reveals what they were on about. On page 22, under the list of performers, you find the words: "Some members of the string sections voluntarily rotate seating on a periodic basis." Bunch of crazy guys, or what?

"We cannot win," said a hapless British Gas spokesman on the Today programme during the week, "We're caught between the Devil and, er ... and a hard place." Mixing metaphors to such a spectacular extent takes real skill, daring and application. Perhaps the water companies, when they next want to explain some foolish and enraging initiative, could go on about being stuck "Between Scylla and, um, the deep blue sea". Maybe the excuse-makers on the Eurostar service would like to try explaining, "you know, when an unstoppable force meets, ah, Charybdis ...". I look forward to hearing the losing candidate at the next by-election curse his luck at "falling between, er ... a rock and, er ... an immovable object".