Elizabeth Heathcote: My strappy little numbers? Sandals

Alas, the early burst of summer has drawn to a chilly close. But not before the spring sunshine had a chance to germinate one of the great wardrobe moments of the year. The move into sandals.

My joy at this annual event is increasingly tempered by the unpleasant baggage that comes with it. The first glimpse of those white legs, unpainted toes and calloused feet, veterans of another year's trudge down the long march of life - all of these need to be confronted and dealt with. But they are mere sideshows to the main event. What the hell to buy this year?

If you are over 30 the chances are that your choice will include, and very possibly be limited to, Birkenstocks or Crocs.

For anyone who hasn't left the house for the past 20 years or so, Birkenstocks are the leather Jesus creepers (and variants) that have dominated the comfy sandal market for most of my adult life. Crocs are the johnny-come-latelys - those brightly coloured American rubber clogs beloved of surfers and health care workers that have been the surprise summer hit of the last couple of years. Crocs look even more absurd to the untrained eye than Birkies, but to be fair there's not a lot in it. Both brands cruise on comfort cool, which storms many a fashion edifice, and both sides claim celebrity fans. Al Pacino and Teri Hatcher apparently swear by their Crocs; rock stars have been kicking back in their Birkies since the Gallagher brothers had their first number one. Both come in his'n 'hers versions and crucially, both are available in children's sizes for the ultimate me-him-and-mini-me, aren't-we-adorable, one-stop shopping experience. And of course there are cheap copies galore.

Now, I am no fashion head, as may be evident, but like most women, I still want to be a contender, and that means I need to get it right. I don't have an office to contend with and the mums in my playground are not a judgmental bunch, but naturally there is sly note-taking. (It always makes me laugh when men think we're eyeing each other up because of our lesbian side. It's the outfits, stupid.) I am conscious of falling into the "older mum" and "still carrying baby weight" categories, which, as in the rest of life, don't help. And comfy shoes are a fashion knife-edge - nothing dates you faster than getting it wrong. Shallow as it may seem, the idea that I might be described as "mumsy" brings tears to my eyes.

A trip to the local Birkenstock stockist is a journey through my past. How I smirk at the two strap Arizona that I bought in brown a good 15 years ago - so Nirvana then, so frumpy today! (Interestingly, most men got stuck at this first stage of the Birkenstock "journey" and are still replacing their Arizonas when they fall apart. More evidence of unsophisticated wiring? Or are they just less gullible than us?) A row of single strap Madrids brings back summer after summer in the early Zeroes, first in white or brights, then flowery, then pastel shades.

Madrids were casual with skirts and groovy Scholl-wannabes with jeans, but they look so girly now, flimsy somehow - and definitely wrong. The Ramses T-bar style looks promising - I've clocked those on cool girls, but how recently? And what colour? Plain black or brown? Khaki? Silver? "Can I help?" asks the assistant, in a pair of ballet pumps that I recognise as "directional". I panic - could it be that that all possible variants of Birkies are for has-beens? Is it finally over?

The Crocs supplier is heaving with mums and children, and the air is tense with the sort of shrill urgency that jettisons three-month-old babies into music workshops. One woman has five pairs piled up in different colours and sizes and is still shopping; another looks edgy as she waits to bag an assistant who might finally be coming free. There are Crocs spilling out of open boxes by the storeroom entrance and women are rifling through. I pick out a pair that seem to be my size - my soles are floating on a lawn of rubber grass; I can see the appeal. The woman with five pairs picks out another, in orange, "for Michael - we'll need them in Cornwall". I try to find out how much the children's Crocs cost but can't get anyone's attention, so I ask another mum "£20, I think," she says, and eyes the pair in my hand. "What size are those? Are you buying them?"

I give them to her and push my way back on to the street through a group of women clustered outside the door. Phew! What the hell just happened? I'm not sure but one thing I do know, those were Posh Mums. It makes sense of course, there's something distinctly beautiful-children-running-through-sand-dunes-near-the-holiday-home-in-Padstow about Crocs and I can't risk getting confused with all that, not in my playground.

In the end I settle for a pair of Birkenstock offshoots, T-bar flip-flop style in metallic black and with a diamanté buckle. I wear them to take my daughter to playgroup in the local park and the sporty twentysomething who runs it makes a beeline. "Oooh, they're nice," she says. "I can't wait to get my Birkies on."

Ding! Round one to me.

Rowan Pelling is away