Standing at the next checkout is the old woman in the blue coat, and I try to avoid her eye. But she spots me, and calls triumphantly, 'I took your advice! I've got something I think she'll really like!'

'Oh good,' I reply, handing my recipe book over to be scanned.

'It's called The Rough Guide to India. Have you heard of it?' says the old woman, showing me the fat blue paperback.

'Oh,' I say. 'Well, yes, but-'

'That's ?24.99, please,' says the girl at my till.

What? I look at the girl in dismay. Twenty-five quid, just for recipes? Why couldn't I have picked up some cheap paperback? Damn. Damn. Very reluctantly, I take out my credit card and hand it over.

Shopping is one thing – being forced into purchases against your will is something else. I mean, I could have bought some nice underwear with that twenty five quid.

On the other hand, I think as I walk away, that's quite a lot of new points on my Club Card. The equivalent to… 50p! And now I'll be able to make loads of delicious, exotic curries and save all that wasted takeaway money. Really, I've got to think of this book as an investment.

I don't want to boast – but apart from that one purchase, I do incredibly well over the next couple of days. The only things I buy are a really nice chrome flask to take coffee into the office (and some coffee beans and an electric grinder – because there's no point taking in crappy instant coffee, is there?). And some flowers and champagne for Suze's birthday. But I'm allowed to get those, because, as David E. Barton says, you must treasure your friends. He says the simple act of breaking bread with friends is one of the oldest, most essential parts of human life. 'Do not stop giving your friends gifts,' he says. 'They need not be extravagant – use your creativity and try making them yourself.'

So what I've done is to buy Suze a half-bottle of champagne instead of a whole one – and instead of buying expensive croissants from the patisserie, I'm going to make them out of that special dough you get in tubes.

In the evening we're going out to Terrazza for supper with Suze's cousins Fenella and Tarquin – and, to be honest, it might be quite an expensive evening. But that's OK, because it counts as breaking bread with friends. (Except the bread at Terrazza is sun-dried tomato focaccia and costs ?4.50 a basket.)

Fenella and Tarquin arrive at six o'clock on Suze's birthday, and as soon as she sees them, she starts squealing with excitement. I stay in my bedroom and finish my makeup, putting off the moment of having to go out and say hello. I'm not that keen on Fenella and Tarquin. In fact, I think they're a bit weird. For a start, they look weird. They're both very skinny – but in a pale, bony way – and have the same slightly protruding teeth. Fenella does make a bit of an effort with clothes and makeup, and doesn't look too bad. But Tarquin, frankly, looks just like a stoat. Or a weasel. Some bony little creature, anyway. They do strange things, too. They ride around on a tandem and wear matching jumpers knitted by their old nanny and have this stupid family language which no-one else can understand. Like they call sandwiches 'witchies'. And a drink is a 'titchy' (except if it's water, which is 'Ho'). Take it from me, it gets really irritating after a while.

But Suze loves them. She spent all her childhood summers with them in Scotland and she just can't see that they're a bit strange. The worst thing is, she starts talking about witchies and titchies when she's with them. It drives me mad.

Still, there's nothing I can do about it – they're here now. I finish brushing on my mascara and stand up, looking at my reflection. I'm pretty pleased with what I see. I'm wearing a really simple black top and black trousers – and, tied loosely round my neck, my gorgeous, gorgeous Denny and George scarf. God that was a good buy. It looks fantastic.

I linger a bit, then resignedly open my bedroom door.

'Hi, Bex!' says Suze, looking up with bright eyes.

She's sitting cross-legged on the floor of the corridor, ripping open a present, while Fenella and Tarquin stand nearby, looking on. They're not wearing matching jumpers today, thank God, but Fenella's wearing a very odd red skirt made out of hairy tweed, and Tarquin's double-breasted suit looks as if it was tailored during the First World War.

'Hi!' I say, and kiss each of them politely.

'Oh, wow!' cries Suze, as she pulls out a picture in an old gilt frame. 'I don't believe it! I don't believe it!'

She's looking from Tarquin to Fenella with shining eyes, and I look at the picture interestedly over her shoulder. But to be honest, I can't say I'm impressed. For a start it's really dingy – all sludgy greens and browns – and for another start, it just shows a horse standing still in a field. I mean, couldn't it have been jumping over a fence or rearing up or something? Or maybe trotting along in Hyde Park, ridden, by a girl in one of those lovely Pride and Prejudice dresses.

'Happy Bad Day!' Tarquin and Fenella chime in unison. (That's another thing. They call birthdays bad days, ever since… Oh God. It really is too boring to explain.)

'It's absolutely gorgeous!' I say enthusiastically. 'Absolutely beautiful!'

'It is, isn't it?' says Tarquin earnestly. 'Just look at those colours.'

'Mmm, lovely,' I say, nodding.

'And the brushwork. It's exquisite. We were thrilled when we came across it.'

'It's a really wonderful picture,' I say. 'Makes you want to just… gallop off over the downs!'

What is this drivel I'm coming out with? Why can't I just be honest and say I don't like it?

'Do you ride?' says Tarquin, looking up at me in slight surprise.

I've ridden once. On my cousin's horse. And I fell off and vowed never to do it again. But I'm not going to admit that to Mr Horse of the Year.

'I used to,' I say, and give a modest little smile. 'Not very well.'

'I'm sure you'd get back into it,' says Tarquin, gazing at me. 'Have you ever hunted?'

Oh for God's sake. Do I look like Ms Country Life?

'Hey,' says Suze, fondly propping the picture against the wall. 'Shall we have a titchy before we go?'

'Absolutely!' I say, turning quickly away from Tarquin. 'Good idea.'

'Oooh yes,' says Fenella. 'Have you got any champagne?'

'Should have, says Suze, and goes into the kitchen.

At that moment the phone rings and I go to answer it.

'Hello?'

'Hello, may I speak to Rebecca Bloomwood?' says a strange woman's voice.

'Yes,' I say idly. I'm listening to Suze opening and shutting cupboard doors in the kitchen and wondering if we have actually got any champagne, apart from the dregs of the half-bottle we drank for breakfast…

'Speaking.'

'Ms Bloomwood, this is Erica Parnell from Endwich Bank,' says the voice, and I freeze.

Shit. It's the bank. Oh God, they sent me that letter, didn't they, and I never did anything about it.

What am I going to say? Quick, what am I going to say?

'Ms Bloomwood?' says Erica Parnell.

OK – what I'll say is, I'm fully aware that my overdraft is slightly larger than it should be, and I'm planning to take remedial action within the next few days. Yes, that sounds good. 'Remedial action' sounds very good. OK – go.

Firmly I tell myself not to panic – these people are human – and take a big breath. And then, in one seamless, unplanned movement, my hand puts down the receiver. I stare at the silent phone for a few seconds, not quite able to believe what I've just done. What did I do that for? Erica Parnell knew it was me, didn't she? Any minute, she'll ring back. She's probably pressing redial now, and she'll be really angry…

Quickly I take the phone off the hook and hide it under a cushion. Now she can't get me. I'm safe.

'Who was that?' says Suze, coming into the room.

'No-one,' I say, feeling slightly shaky. 'Just a wrong… Listen, let's not have drinks here. Let's go out!'

'Oh,' says Suze. 'OK!'

'Much more fun,' I gabble, trying to head her away from the phone. 'We can go to some really nice bar and have cocktails, and then go on to Terrazza.'

What I'll do in future, I'm thinking, is screen all my calls. Or answer in a foreign accent. Or, even better, change the number. Go ex-directory.

'What's going on?' says Fenella, appearing at the door.

'Nothing!' I hear myself say. 'We're going out for a titchy and then on to sups.'

Oh, I don't believe it. I'm turning into one of them.

As we arrive at Terrazza, I'm feeling a lot calmer. Of course, Erica Parnell will have thought we were cut off by a fault on the line or something. She'll never have thought I put the phone down on her. I mean, we're two civilized adults, aren't we? Adults just don't do things like that.

And if I ever meet her – which I hope to God I never do – I'll just keep very cool and say, 'It was odd what happened, that time you phoned me, wasn't it?' Or even better, I'll accuse her of putting the phone down on me (in a joky way, of course).

Terrazza is full, buzzing with people and cigarette smoke and chatter, and as we sit down with our huge silver menus I feel myself relax even more. I love eating out. And I reckon I deserve a real treat, after being so frugal over the last few days. It hasn't been easy, keeping to such a tight regime, but somehow I've managed it. And I'm keeping to it so well! On Saturday I'm going to monitor my spending pattern again – and I'm sure it'll have gone down by at least 70 per cent.

'What shall we have to drink?' says Suze. 'Tarquin, you choose.'