It wouldn’t be true to say that Roger saw the funny side, or had glimpses of perspective, or anything like that; but there were one or two moments on Christmas morning when he was able to remember that things hadn’t always been like this. At about quarter to seven, for instance, he was downstairs on the sitting-room carpet trying to assemble a plastic robot which turned into a car and also into a gun and uttered set phrases through a speaker-box and could also be operated by remote control. The problem was that it was a very complicated toy: not only was it highly fiddly, with hundreds of small parts, but it came with instructions which seemed designed with the conscious intention to confuse and mislead. Beside and around and beneath Roger, the floor was covered in pieces of infant Lego from several different kits, which Conrad had torn open and thrown around the room while his back was turned. Joshua had upended the gigantic box of Brio he’d been given, so a substrate of wooden train tracks and engines lay mixed in with the plastic, paper, torn boxes, and various other toys which had been briefly experimented with and discarded. Conrad had already broken one of his main toys, a racing car with green stripes and a driver who was supposed to beep when you pressed down on his head, but who had been jammed down so firmly that he didn’t stop ringing, like an alarm. Roger hadn’t been able to find either an off switch or a battery hatch to open so he had smashed the toy with a hammer. Conrad was still sniffling about that, while fiddling with one of his new lightsabers.

No, Roger had not seen the funny side. But there had been a moment when, after looking at his watch, he had thought: I can remember when Christmas morning would start at about half past ten with a glass of Buck’s Fizz in bed. Now it begins at half past five, with a test of my fine motor skills and ability to read Korean.

There was no sense in which Roger had taken things lying down. The previous night, straight away on getting Arabella’s note, he had bundled a protesting Conrad off to bed, then hit Google and looked up nanny agencies (not forbearing to try things like ‘emergency nannies’, ‘last-minute nannies’ and ‘crisis nannies’). He had left messages on the answering machines of seven different agencies and knew that he was going to hire the very first person who was available. So help was at hand. But help being at hand was no help, not right in the here and now, with his wife away wherever the hell it was she was, and his parents a. in Majorca and b. useless.

After leaving the nanny messages, Roger had held the phone in his hand for a long time. The question was what message to leave on Arabella’s mobile. He knew her well enough to know she wouldn’t answer it, or even have it switched on; he also knew that she’d be checking her messages, desperate to know how her plan had gone. His first impulse was to ring her up and rant, denounce, deplore, ask her who she thought she was, tell her just how lazy she was, just how little a clue she had, and by the way they were £970,000 short of where they needed to be this holiday. To tell her not to bother coming back; to tell her that the locks would be changed; that all further contact between them would have to be through solicitors; that her children now hated her; and more of the same.

Roger also knew that she would be expecting and to some extent depending on a reaction along those lines. He had a simple maxim for all competitive or adversarial situations: work out what the other party least wants you to do, and then do it. Relieving your feelings was fun, but the best course of action was to make things as difficult as possible for the person trying to make things difficult for you. On that basis, the thing that would most freak out Arabella was for him to be cool, to act as if nothing could have disconcerted him less than having the kids on his own over Christmas. She would be relying on drama, on fuss; probably on an explosive row followed by lavish making-up, mainly engineered by him. OK, fine. He would give her the silent treatment. Knowing Arabella, she would have gone to some posh spa or hotel. Well, she could stew there. He’d be fine with the boys. How hard could it be?

Now it was Christmas morning, and as if to answer that question, Joshua, who had insisted on having his night-time nappy taken off, was making it clear that he needed to go to the toilet – which he did by pointing to the sitting-room door and roaring. Roger picked him up with his right hand, carried him up to the half-landing, and opened the loo door with his left. There should have been a potty, but there wasn’t: the last thing Pilar did when she left on a weekend or holiday was disinfect all the potties with Dettol and leave them to dry in the boys’ bathroom, but Roger didn’t know that, so he tried to hold Joshua in place on the loo seat and stop him falling into the toilet bowl while his son did whatever he had to do. Joshua seemed to object to that procedure; he didn’t like being held up with his bum in the air over the loo.

‘There’s nothing else for it,’ said Roger. Joshua twisted his upper body round and tried to bite Roger on the arm. ‘Would you rather I let you fall in?’ asked Roger. The answer to that seemed to be in the affirmative. Joshua now began wriggling from side to side as hard as he could, with the full unrestrained strength of a three-year-old. He had the concentrated force of pure will and was also stocky, muscular, a tube of force and determination. He suddenly changed direction and bucked upwards, catching Roger right on the point of the chin with a ferocious upward head-butt.

‘Fuck!’ shouted Roger, his eyes stinging with tears. As his grip weakened, he felt Joshua slip. The little boy fell forward off the loo seat, seeming to be in tears before he landed on the floor. At that point, with no warning, he began to shit. A spray of excrement, not entirely liquid in texture but not solid either, came out of Joshua’s bum and as if it were a form of propellant he began crawling at amazing speed out of the loo, heading for the landing. Roger, head ringing, one hand on his mouth and jaw, lunged after him but he was too slow and Joshua made it onto the cream carpet before his father could catch him. Excrement was still coming out of Josh’s bottom and he was still crying. Roger was crying too thanks to the head-butt, which had made his eyes fill with tears. He lunged again and grabbed Josh with his right arm before he could make it down the stairs. Roger, wrestling with his son, noticed something that it was not helpful to notice: that the colour of the fresh shit-swirls on the carpet was exactly the shade of a perfectly made cappuccino. Then Joshua shat again, this time down the arm of Roger’s dressing gown. The shit was liquid and hot. It smelt very bad. Then the front door rang.

‘Fuck!’ said Roger, under his breath, but not sufficiently under his breath, because Joshua, smiling now that he had relieved himself, also said ‘Fuck!’ Roger decided that whoever it was at the door could sod off.