‘Oh God. Oh God.’ I squeeze my eyes closed and press my lips together, clapping a hand over my mouth. I’m not sure if I’m trying to stay quiet or squeeze away the pain through sheer force of will.

‘We took her for a little walk in the park. It was such a nice day, but we kept it very slow. We just wanted her to get some fresh air.’

‘I know. It’s okay.’ My parents treat Tabby with kid gloves, even more than I do. They’re so devoted and so conscientious, and I won’t have them beating themselves up over something that could have happened on my watch. ‘What happened?’

‘Her fingers and mouth turned blue, and her eyes went glassy. It was so terrifying. We didn’t know what to do, so your dad carried her out to the street and flagged down a cab. We’re at Denmark Hill.’

‘What have they said? What are her other symptoms? Have they triaged her? They need to take her sats. Have you shown them the form?’

The questions are pouring out of me now in a deluge of panic. I trust my parents implicitly. I know they’d run into traffic for my daughter, just as I know Mum has an oximeter in her handbag and a copy of Tabby’s medical information form on her phone. But nobody knows her condition as well as I do. No one has more experience than me of managing her A&E trips, producing all the information and educating every single medic who has contact with her.

In short, no one can advocate for Tabby like me when it’s crunch time.

‘We gave them the list,’ Mum tells me, her voice still quavery. ‘Um, a nurse said she’d be triaged within the next few minutes.’ She’s a level-headed woman, but the pair of them are getting on in years, and an emergency like this is discombobulating for anyone. They’ve been with me and Tabs to A&E a couple of times, but they’ve never taken her by themselves.

‘Have you taken her sats?’ I ask in a rush. ‘Do you have her knees to her chest? You need to. It prioritises the blood flow to her lungs.’ My tears are falling freely now. I can’t help it. We’re so close. We’re so fucking close to this operation, to getting Tabby a solution that will last her until she’s in her early teens, at least.

When your child is oxygen deficient, time is everything. Any dithering around or failure to take Tabby’s condition seriously could lead to all sorts of horrific outcomes. I can’t even think about it. I feel so fucking helpless as I listen to my parents fannying about. ‘Robert, she needs to tuck her knees up higher. That’s it, Tabs. Good girl.’