Will my children remember me as a good mother? Or will they have me down as a chaotic screamer capable of vacillating (depending on how hungry or tired I am) from Mrs Darling to Joan Crawford?

Everyone starts off in the parent game wanting to be perfect. I’m talking about mothers, that is. Dads just have to turn up. Maybe they can throw in a couple of feeds, a nappy change or two and a saunter with the baby sling. If so, they will be hailed as perfect dad and probably get a couple of extramural sexual invitations into the bargain.

Mothers, however, are living through a permanent exam wherein we must meet some impossible ideal: we must be endlessly patient and available, always cheerful, never yell, not project our own neuroses on our children, have perfectly turned out children, cook like Nigella and never be too tired for sex.

A recent article in New York magazine by Ayelet Waldman, The Bad Mommy Brigade, conducted a poll to try to discover who are western culture’s ideal mothers: it came up with Marmie from Little Women and Mary Poppins (without her leaving at the end of the film and being the nannie, obviously). But as the writer remarked tartly, “Both are fictional characters, it’s as if an Olympic swimmer were to beat herself up for not being the Little Mermaid.”

It’s interesting that it is so hard to come up with ideal mother icons who actually exist in the real world, since so many of us seem permanently convinced that we are not measuring up to some bizarre notion of perfection. This is often fuelled by photographs of gorgeously pouting celebrities in size 2 jeans pushing their little darling through the park in a Hello!-induced haze – Gwyneth Paltrow with her Bugaboo anyone?

It is an obsession that has produced a whole yummy-mummy industry propagated by companies such as Boden who sell idealised images of happy families where mum doesn’t do anything mundane like actually go to work, but hangs out on the beach feeding the children homemade cookies and playing cricket.

The single defining characteristic of iconic good motherhood is self-abne-gation; everything she does is for her family’s health and happiness, she is a creature with no ego, no desires of her own – you can bet she never zones out and starts thinking about work while reading her children fairy tales.

But nothing could be a more perfect puncture to standard 21st century maternal guilt than a quick scamper through the annals of truly Olympian maternal shortcomings. And as with so many things, the Americans really know how to go over the top when it comes to “bad mommies”. The gold medal must go to Wendy Cook, a prostitute in Saratoga Springs, who snorted cocaine off her baby’s stomach while she was breast-feeding. (The logistics of this rather defeat me, I mean, how could she have reached? And if you are in this league of mothering, why breast-fed? Surely a bottle would be easier – but I suppose you have to get out of bed to get a bottle and a breast quiets a yelling baby quicker.)

It is the anti-perfect-mother backlash which seems to be fuelling an obsession with the ups and more often downs of poor old Britney Spears. Anyone who doubts the astonishing pull of the freak show that is Britney’s doomed attempt to seek custody of Sean Preston, 2, and Jayden James, 1, should mull over this. A leading professor from the University of California, Los Angeles, has estimated the Britney story is worth hundreds of millions of dollars to US tabloid TV and magazines. It is thought that she has generated $1 billion in value to the US media over the past three years. Britney on the cover of Us Weekly bumps sales up by 20%.

We are not immune from such mummy watching closer to home: surely part of the obsession with Kate Moss’s 34th birthday celebrations last week (which began at 2.30pm on Wednesday and continued until lunchtime on Thursday, via all manner of different venues – one reveller arrived at her house at 8am with a full bottle of Stolichnaya vodka, so they weren’t just drinking orange juice all night that’s for sure) is the fact that she too is a mother.

But motherhood Moss-style isn’t like it is for the rest of us. She always seems to have a babysitter and never seems to be too knackered for a night on the razzle. Although some of those nights out seem to be taking their toll on Moss’s million-pound visage: she looked distinctly weather-beaten after the festivities.

Stephanie Calman, founder of the Bad Mothers Club, a British website that “takes a much needed swipe at the guilt-inducing perfect-parent philosophies” now has 10,000 members, and her book, Confessions of a Bad Mother, was a bestseller. She thinks women are revelling in stories such as Britney’s because they stop modern mothers feeling guilty about their own behaviour.

“All I did was simply expose the judgmental attitude that’s going on with motherhood nowadays,” she says, explaining why her site and book have been so popular. “Women who signed up were like refugees. For trying to be a human being, for God’s sake. It’s ludicrous that you are made to feel guilty if you decide to put your kid in front of the telly and have a cup of coffee.”

Has she ever done that? “My children have always been forced to watch much more TV than they wanted to,” she says affably. “But really the light-bulb moment for me came when I realised I didn’t have to do things perfectly. I have never sterilised a bottle. I have never made a party bag. I think trying to live up to a perfect ideal is highly damaging, because the more you try to be perfect, the more you lose your own identity.”

She tapped into this market by accident after she admitted on This Morning to smacking her child.

“I said I had smacked my daughter when she hurled her welly into someone’s lunch at the Royal Horticultural Society. And I felt terrible afterwards. When I got home there were 200 e-mails from viewers saying, ‘We’ve been there too’.”

Knowing other mums aren’t perfect is comforting. We may sometimes lose our temper with our children. We may sometimes strap them into their buggies and leave them yelling in the middle of the sitting room. We may even throw something precious of theirs in the bin. Deliberately. But at least we have never behaved quite like poor old Britney, which is something to hold on to in the dark hours of the morning when that teeth-grit-ting demand of “Mummeeee! I need a peeeee” comes issuing from the little bedroom for the umpteenth time.

While the Spears story has a core of grief and pain, it is an undeniable truth that reading about someone else screwing up makes your life look a bit better. It’s a nasty truth, but it is true.

And what a relief it is, given the pressure on the rest of us. We all know that after the terrifying ordeal of giving birth (and don’t you dare tell anyone if you used pain relief) we must embrace breast-feeding, get into our prebaby jeans immediately and never, ever, complain about getting up in the night, cracked nipples or piles. We must never be cross. We must never be selfish. We must never mourn our old, prebaby life. Some weaklings will give in, buy a vat-load of formula milk and hire a £1,000-a-week maternity nurse. This must not be you. Outwardly, you will loftily criticise them. Inwardly, you will bitterly envy them.

The test never slackens up. Even if you resume your premothering career, and pay someone else a small fortune to look after your child, you will find yourself tripping over the hurdles of nanny envy (particularly when your little darling starts calling Nica from Poland “Mummy”) and more guilt than seems humanly possible. And if you don’t go back to work, there is the danger of going demented thanks to a weekly routine of Tick Tock Clock, CBeebies and singalongs at the library where the most intellectually challenging event is when some bright spark arrives with a new verse for The Wheels on the Bus.

And if your self-induced perfect-mother ideal isn’t a tight enough corset for you, there are legions of self-appointed experts out there, mummy watchdogs only too happy to turn the thumbscrews when you mess up.

“All this pressure on mothers,” says Kathy Lette, comedic author of novels such as How to Kill Your Husband. “Perfect mums only exist in American sitcoms. Any mother who says she copes all the time is either lying or taking lots of drugs. Just remember that Mowgli survived, right?”

And at least you aren’t Britney.

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