And there’s a really lovely velvet jacket, age 12, only £20, down from £120! It would be a total mistake not to get it.

I can’t believe how far-sighted I’m being as I fill my basket with more and more clothes. I’ve practically bought all Minnie’s key pieces for the next ten years, at rock-bottom prices! I won’t need to buy her anything else!

As I pay for the lot I feel a glow of self-satisfaction. I must have saved hundreds.

‘Well!’ Nanny Sue seems a bit lost for words as the assistant hands me three huge bags. ‘You bought a lot more than a pair of socks!’

‘Just thinking ahead.’ I adopt a wise, motherly tone. ‘Children grow so quickly, you have to be prepared. Shall we go and get a coffee?’

‘Starbucks?’ chimes in Minnie at once. She’s been watching me attentively, and has insisted on wearing the age 7–8 pale-pink raincoat, even though it’s trailing on the floor. ‘Starbucks-muffin?’

‘We might just have to go to a chain coffee shop.’ I try to sound regretful. ‘They may not have an organic health-food cooperative.’

I consult the map – and to get to the food court we’re going to have to walk past all the designer shops. Which is fine. I’ll be fine. I just won’t look in the windows.

As the three of us start walking along, my eyes are focused straight ahead, on that pointy metal modern sculpture hanging down from the ceiling. It’s fine. It’s good. Actually, I’ve got used to not shopping. I barely miss it at all …

Oh my God, it’s that Burberry coat with the frills that was on the catwalk. Right there in the window. I wonder how much …

No. Keep walking, Becky. Don’t look. I close my eyes until they’re two squinty slits. Yes. This is good. If I can’t actually see the shops—

‘Are you all right?’ Nanny Sue suddenly notices me. ‘Rebecca, are you ill?’

‘I’m fine!’ My voice sounds a bit strangled. It’s been so long since I shopped. I can feel a kind of pressure building up inside me; a kind of bubbling desperation.

But I have to ignore it. I promised Luke. I promised.

Think about something else. Yes. Like when I did that labour class and they said you breathe to distract yourself from the pain. I’ll breathe to distract myself from the shopping.

Breathe in … breathe out … breathe in … oh my God, it’s a Temperley dress.

My legs have stopped dead. It’s a white and gold Temperley evening dress, in a shop called Fifty Percent Frocks. It has stunning embroidery around the neck and it sweeps to the floor and it looks like something straight off the red carpet. And it has a sign by it, saying ‘Extra 20% off today’.

My fingers are gripped round my shopping bags as I stare through the window.

I can’t buy this dress. I musn’t even look at it.

But somehow … I can’t move, either. My feet are rooted to the polished marble floor.

‘Rebecca?’ Nanny Sue has come to a halt. She peers in at the dress and clicks her tongue disapprovingly. ‘These dresses are terribly expensive, aren’t they? Even on sale.’

Is that all she can say? This is the most beautiful dress in the world, and it’s a fraction of its full price and if I hadn’t made that stupid promise to Luke …

Oh my God. I have the answer. In fact, this could be the answer to a lot of things.

‘Minnie.’ Abruptly I turn to her. ‘My lovely, precious little girl.’ I bend down and cradle her face tenderly between my hands. ‘Darling … would you like a Temperley dress for your twenty-first birthday present?’

Minnie doesn’t answer, which is only because she doesn’t understand what I’m offering her. Who wouldn’t want a Temperley dress for their twenty-first? And by the time she’s twenty-one it’ll be a rare vintage piece! All her friends will be really envious! They’ll all say, ‘God, Minnie, I wish my mother had bought me a dress when I was two.’ People will call her The Girl in the Vintage Temperley Dress.

And I could borrow it for Luke’s party. Just to try it out for her.

‘Muffin?’ Minnie says hopefully.

‘Dress,’ I say firmly. ‘This is for you, Minnie! This is your birthday present!’ Firmly I lead her into the shop, ignoring Nanny Sue’s startled look. It takes me ten seconds to sweep the place and realize the Temperley dress is the best thing they’ve got. I knew it was a bargain.

‘Hi!’ I say breathlessly to the assistant. ‘I’d like the Temperley dress, please. At least … it’s for my daughter. I’m buying it in advance, obviously,’ I add, with a little laugh. ‘For her twenty-first.’