For her part, she couldn’t disguise her delight at having an ally against Anna on holiday with her. I made her look amazing: I wasn’t monitoring how long Sam played on the iPad to the last millisecond, I didn’t ration out sweets with wartime alacrity and I didn’t fall on the floor if Sam wore the same T-shirt complete with ice cream splodge two days in a row. Presumably not being anywhere near ‘as bad as Maggie’ had eased the pain of not being as bloody marvellous as Caitlin.

And that was before anyone drew a physical comparison between Caitlin and me – I had no doubt she’d have been wafting about in an itsy-bitsy barely there bikini while I flubbered about in my one-piece swimming costume. The revulsion on Francesca’s face every time Nico rubbed suntan lotion into my back didn’t do a lot for my confidence. My fear of getting swimming costume sag and looking down to see half a squirrel of pubes hanging out of my cossie was leading to a ridiculous amount of undercarriage monitoring and rearrangement.

But today, I was feeling good. I’d caught enough sun to take the blue tinge off my white limbs and the warm weather had acted like Miracle-Gro on my optimism. I took off my sarong without looking at Anna sitting there with her stomach suspended like a smooth hammock between jutting hip bones. Too much watercress and not enough Mars Bars. Next time I saw an article in the paper about why chocolate/vats of wine/sugar-covered doughnuts were good for you, I’d bring it out with a flourish. Plus one on how being thin can suck the joy out of your life and make people hate you.

However, within moments of getting into the pool, I stopped worrying about that ‘big bum coming through’ stuff and found a childish pleasure in joining in volleyball, keepy-uppy, dodgeball. The swimming pool turned out to be a place for bonding and bridge-building. I’d often had to ride a bike when I’d run out of money for petrol, so despite being a little short-arse, my legs were perfect powerhouses for leaping up in volleyball. My school had only had a scrubby patch of waste ground masquerading as playing fields, so apart from a ‘sports day’ once a year where there was more emphasis on sack races than sprinting, I’d never had much opportunity to find out if I was competitive. But aged thirty-five, I had a definite killer instinct for battering a ball over the net. Even Sandro joined in with ‘Maggie, Maggie, Maggie, Go, Go, Go’ from the edge of the pool.

The unexpected spin-off was that although Francesca was still talking to me in monosyllables, her desire to win meant she wanted me on her team. When she picked me above Nico, I didn’t immediately move to her side of the net in case I’d heard wrong. But as she beckoned me over, I felt all that hard-done-by feeling loosen, as though I’d taken everything far too personally.

When we beat Massimo and Nico, we high-fived and a tiny shoot of belief that we might move forwards uncurled. Even though I was still secretly replaying my spectacular winning smash in my mind, I said, ‘You deserve a medal! You were brilliant!’

Her face creased into a big grin, then, almost as though she’d reminded herself I was the enemy, her smile faded.

‘Shame I haven’t got a jewellery box to keep it in,’ she said, plunging into the water and disappearing off down the other end of the pool doing butterfly. So bloody Farinelli. Nothing so common for them as a bit of breaststroke or non-descript doggy-paddle.

I repeated, ‘Baby steps, one at a time’ to myself.

Nico gave me one of those smiles I was beginning to dread, the one full of sympathy that said, ‘Be patient, we’ll get there.’ I did sometimes have an overwhelming desire to sing, ‘There are Worse Things I Could Do’, accompanied by some chicken-wing movements and Olivia Newton-John jiving not strictly in keeping with the song.

Just occasionally I’d like him to pull her up on her bloody rudeness.

So, with this thought clouding my original hopes for a guilt-free sunny day, I didn’t offer to go with Nico and Anna to the market to do the food shopping. Even though it was my turn, as marked in pink highlighter on Anna’s inflexible little chores rota, I was going to rebel: sit on my sunlounger and read ‘one of those dreadful celebrity gossip magazines’ instead of pontificating about whether tonight’s dinner required a porcino mushroom, an asparagus tip or a bloody snuffle of truffle. Nor was I in the mood to appease Anna’s endless fishing for compliments with arse-licky answers: ‘Yes, the castle is fantastic. Yes, it is a real privilege to be here. No, Sam hasn’t ever travelled anywhere as lovely before.’

Instead I wrapped myself in a towel, waving a cheery goodbye, watching to see if there was a furtive dip of the head as Anna whispered a little dig about me out of earshot. I wasn’t disappointed. I wanted to chase after them down the cobblestones, wobble my fat thighs at her, grab my belly and squidge it into a speaking mouth that said in a high-pitched voice, ‘Go screw yourself’. The temptation to thunder over to her and tell her that even though I could do with stepping through the doors of Slimming World, at least I was faithful and true to her son, unlike Caitlin. I might even share the tongue-twister I’d invented to distract myself when Anna’s Caitlin hyperbole got too much. ‘The pin-thin paragon of all things Pilates with a penchant for penises.’

Massimo appeared carrying a tray of beer. ‘Pre-lunch tipple?’

Thank God for Massimo and his free-flowing booze. I swore Anna had put little marks on the gin bottle in case I had an unauthorised slurp.

Just as I was thinking the day was improving, Massimo said, ‘I’ve booked us all tickets to the open-air opera tonight.’ He looked like one of the excited emojis on Francesca’s phone.

I stared at him, hoping he was joking.

But no. He was serious. ‘What’s the matter?’

‘I’ve never been to the opera. I’m worried I won’t understand it.’ I felt hot just thinking about sitting through two hours with everyone else nodding along, following the story whereas I’d probably feel like Sandro, forced to go to Mandarin lessons, unable to distinguish between the word for a marshmallow or a mop bucket.

Massimo threw his hands up in mock horror. ‘Never been to an opera! You’ll love it… words and wisdom joined together in perfect musical harmony. You sit next to me, I’ll help you out.’

I wished I’d gone with Nico now. I was pretty sure he wouldn’t be thrilled to hear the news.

I pretended I needed to cool down to escape the conversation and swam over to Mum. Massimo had managed to persuade her into the pool despite the fact that she’d never learnt to swim. She sat on the steps in the shallow end, a little Buddha in blue, holding her head out of the water like a nosy ostrich. I’d let Massimo break the news of this evening’s entertainment to her.

Mum kept trying to encourage Sandro in. ‘Aren’t you hot? Why don’t you put your armbands on and come and sit in here with me? I can’t swim either but it’s lovely here on the steps. You’ll be quite safe because I’ll murder anyone who gets my hair wet.’

God bless Mum passing her pacifist tendencies onto the next generation. Thank God Anna wasn’t there to rev up her scissors for snipping a piece out of the paper about the effect of aggressive language on children.

Sandro shook his head. He was arranging pebbles into a shape on the paving stones, sitting by Lara’s sun lounger. I wondered if he minded his dad spending all of his time with Sam and Francesca.

I got out of the pool and dried myself off, intending to redress the balance a bit and see if Sandro wanted to come up onto the ramparts with me to do some drawing, while I took a few photos. The colours of the countryside, the sunflowers and poppies, had given me an idea for a floral patchwork design.

But before I could walk over there, a little altercation broke out, with Lara and Massimo talking to each other in hissy voices, the sort I used on Sam when I didn’t want everyone to know I was telling him off for picking his nose. Massimo had his hands on hips, jerking his head to the pool, then to Sandro. Not for the first time I was grateful I’d been able to bring up Sam on my own during those crucial first years. The pitying looks that I was ‘doing it all myself’ were nothing compared to the freedom of not having to take into account someone else’s views on what was good for Sam.

Lara and Sandro had exactly the same ‘waiting for this to be over’ expressions on their faces. For someone who was so open, so out there with his thoughts and ideas, I could see why Massimo got frustrated with Lara. As much as I enjoyed her company, trying to resolve problems with her must be like shouting over a six-foot high garden wall when you couldn’t see whether the person was still listening on the other side or long gone, sipping coffee at their kitchen table while you bellowed your suggestions and solutions into oblivion. Sandro had inherited the same trait of stonewalling. I only knew he was taking in my suggestions for his art when I saw his drawings.

Sandro pushed himself slowly to his feet. Lara fussed about, putting extra air into his armbands, wetting them in the pool and forcing them up over Sandro’s skinny little arms. He flinched as Sam splashed him when he was trying to tip Francesca off her lilo. I went over to ask them to calm it down.

Sam looked up, ‘Sandro’s such a loser. Why does he make such a fuss about everything?’