Christmas morning had gone much as she expected; Kes opening his stocking at dawn, lots of ‘ooohs’ and ‘aaaahs’ and ‘good for Santa!’, her hangover thumping; losing the fight for the shower (only one hot one possible on their tiny tank); Mack chivvying her to hurry up, his parents looking pointedly at their watches as they waited on their bungalow doorstep at ten; strong tea and shortbread in place of Prosecco and blinis, the Forsyths’ gifts wrapped in last year’s paper – a mountain of Lego for Kes, a set of golf clubs and lesson vouchers for Mack, and bath salts for her, discount price tag still on.

Pax had been no more hurt than usual that her husband was unimpressed by her over-generous gift to him – the still-unnamed deerhound puppy, now asleep in the back of her car – and he’d plainly forgotten that the huge slab of KitchenAid gadgetry he’d given her, for which they had no space in the static caravan, was a duplicate of his gift last year, its twin still in its box in the shipping container that they used as storage. At least they’d both made an effort, and they had lavished Kes with treats. Their one point of mutual, passionate affection was their five-year-old son, as dark-haired and devilishly handsome as his daddy, so hard-won after eight rounds of IVF. The couple’s sexual spark might have died somewhere between laboratory and labour, but a fierce bonfire of parental love had blazed into life with Kes’s arrival, burning their path onwards.

Pax never anticipated that this Christmas she would douse the fire so instantly. Her calmness was legendary. Pax the peacemaker; Pax the level-headed negotiator; Pax who never got angry.

She’d been doing so well, enduring her in-laws’ miserly hosting: folding up paper for next year, a bracing walk, a thimble of Madeira. Thank God she’d brought a hip flask. She’d tolerated Mairi being a well-meaning bully in the kitchen with quiet dignity, undermining her greater culinary expertise (‘this is how Forsyths make bread sauce, Patricia – now chop faster, girl, and I need you to grate that swede next.’). That Mairi had been complimented so effusively over her cold, dry turkey, over-boiled and over-salted veg and Aunt Bessie’s cook-from-frozen roasties, blackened to coal bricks, had admittedly been a surprise, both son and husband in paroxysms of joy (‘You’re the best, Mum!’ ‘Mairi, you have triumphed again!’), her own smile fixed, because relieved as she was that her mother-in-law took all the credit for its awfulness, the food really was awful. But she understood that Mack lavished praise on Mairi because, like all good sons, he loved her so much that she could do no wrong in his eyes. And like all bored husbands, he no longer noticed much of what Pax did. By contrast, every single thing Mack did that day seemed to irritate his wife more than ever.

The way he ate so noisily, talked with his mouth full, filled his own glass and not hers, spoke over everyone, laughed too loudly. The way he encouraged his father to tell those interminable golfing anecdotes, flattered his mother ridiculously, forced both parents to feign interest in his sports bike customisation, every technical detail described in condescendingly over-explained minutiae. His over-competitive cracker-pulling, his badgering insistence Kes try a soggy parsnip until the boy wept. The ‘I think you’ve drunk enough, Tishy’ had been particularly infuriating, as had his pompous ‘Tishy and I will clear up this feast – least we can do after you’ve done all the hard work, Mum.’ It was teeth-grindingly annoying when he handed her back each of the pans she’d washed up to do again. His nasal hum made her want to scream. His lack of eye contact irked her, the way he loaded the dishwasher knives blade up, the sprouts’ fart he let out then blamed on the puppy, his hair combed spivvily sideways, his awful Christmas jumper worn with a suit, his red ears – HIM.