But what of the modern godparent, fighting his or her way down aisles of toys, looking for something, anything, for the child they guiltily realise they have failed yet again to see since last Christmas? Being a godparent can seem thankless and expensive, a sentimental memory of a defunct friendship.
True, there can be perks with the job, such as meeting interesting people. For instance, were you aware of a link between the musical President of Ecuador, Abdala Bucaram, and knife-wielding Lorena Bobbitt? They are both godparents to the child of an Ecuadorean singer. And godparents in Sierra Leone do well: at the wedding of their charges they walk solemnly in front of the bride and groom, while members of the congregation stuff paper money into their pockets.
Of course, in Christian tradition godparents have a key role, renouncing on the baby's behalf "the Devil and all his works", praying "that all carnal affections may die in him" and helping him (it does say "him") to get up to speed on the catechism. In fact, only last month the Church announced that it was trying to brighten up the baptism service - attendance down from 68 per cent of infants in 1950 to little more than 30 per cent today - by being more positive with the water. Out was the half-hearted dab of holy water on the forehead; instead, the Synod recommended a liberal dousing, or even total immersion.
But however much they tinker with the trappings - a return to stone fonts in place of stainless steel "airplane-washbasin" fonts was another proposal - it seems unlikely that the service will make much of a comeback. Not only do many people find the whole concept bizarre - that a tiny baby is riddled with sin and can be saved only by a symbolic wash - but with the job of religious instruction downsized, many godparents feel redundant.
Even a firm believer in Christian baptism, such as Ned Sherrin - "I've always been there at the service for my three godchildren" - had to admit to failure on the teaching side. "Last year I gave my nine-year-old godson an illustrated Bible, as well as a car, and he said very politely, `I don't like to mention this, but you did give me the Bible last year.' I couldn't find a book on teaching the catechism. I do think there is a gap in the market there."
And as if the decline weren't enough, the Church has also, as usual, got its surplice in a twist over the issue of gays and godparents. Last year the vigilant curate of St Peter's, in the Hampshire town of Farnborough, discovered that one of the prospective godparents at a coming christening was gay, and refused to allow him to participate. What's more, she was backed up by her boss, Canon Boddington, who pointed out that the church "did not condone homosexual acts". Of course, you can never be too careful. Shortly before her death, the top model Margaux Hemingway went public with a claim that her godfather had molested her. No homosexual he.
For the aristocracy, christenings are not only an excuse for dressing up, they also add a useful arrow to their already bulging social quiver. Getting a royal is a social coup - Prince Charles has 26 godchildren and Diana, Princess of Wales 16 - but even a baby such as Lady Amelia Windsor, daughter of the Earl and Countess of St Andrews (to pick one at random from a newspaper announcement) is probably going to be OK. Making sure she goes to lots of balls will be the Hon Georgina Stonor, Lord Ralph Kerr, Mrs Jack Hanbury-Tenison and the Hon Anthony James.
But if you are not comfortable in the Christian club, and can't claim exotic or social connections, are you doomed to be the bearer of gifts, waving a bit of plastic once in a while to magic a Barbie or a Ken? Not necessarily. To begin with, make yourself memorable. "I once had a good tip from Edith Sitwell," remarks Ned Sherrin. "She told me to send presents on my own birthday. That meant I didn't have to try to remember when their birthday was, and it was more of a surprise for them. So you stood out as someone unusual."
Another possibility is to be very lax, but come good in the end. A perfect example was my own godmother, the Forties film star Joan Fontaine. I did not see her for years, and she sent nothing except for a soft-focus glamour portrait, which did give me a bit of status at school but hardly compensated for a 17-year present shortfall; however, she more than made up for it when I went to university and she gave me a small allowance which allowed my to buy such all-important study aids as champagne, velvet flares and a cloak.
Of course, even the hopeless ones can have some value. I was given hours of amusement by one of mine, whom I never saw or heard from until I was 21, when he sent me a deeply apologetic letter saying that he planned to leave everything to me in his will, providing his wife, an alcoholic whom I knew he loathed, didn't survive for more than 21 days after his death. It could have been some legal proviso, but for several months I whiled away idle moments planning the perfect murder.
"The best sort of godparent doesn't have any children of their own," opines the writer Sheridan Morley. "I had two wonderful ones who were both gay" (take note, Canon Boddington). "One taught me all about how the London Transport system worked, which for a rather awkward boy up from the country was just wonderful, and the other, who incidentally was the last man to sleep with Isadora Duncan, (he was a teenager and she was about 80) took me to the National Film theatre all the time. He gave me lectures on all the film greats, which I've been using in my books ever since."
It is this sort of really interested and imaginative involvement in a child that points to how valuable a good godparent can be. Richard Olivier, a theatre director, believes that boys in particular benefit from having the help and support of an older male who is not their father. For several years now he has been running an arts and psychotherapy program, called Thunder Road, which is designed for men to explore their masculine side. Now some of the men involved want to act as godparents or mentors to teenage boys.
"Fathers are bad at seeing where a boy ought to be going," says Olivier. "Having another, older male who has thought about what it means to be a man, as someone to chat to or share an interest like football or music, can help them make that difficult transition from boy to adult." The Olivier approach is bit specialised, but many people who don't buy the Christian myth still feel some ritual is appropriate.
For them, one solution could be the Baby Naming Association, formed two years ago, which offers to design a service (a typical one incorporated Christianity and Buddhism, with Bach on the organ and readings from a Celtic poem).
Before the service the godparents sit down with the parents and discuss what they personally want to offer the child, so on the day they can promise something from the heart, instead of mouthing a formula they only dimly believe in.
One starting-point might be this: "Will you accept a commitment to this child, to offer him/her love, friendship and sanctuary so that he/she can turn to you in times of doubt and difficulty with confidence and trust?" It's a bit early to say how effective this approach is - do these godparents still lose touch, or stuff a belated book token in the post once a year? - but it does seem to open up a richer realm of possibility