‘Casey! Come and meet Bear. He’s a key member of the team,’ Jed says.

I smile, but the girl – Casey – backs away, her face twisting with disgust. ‘There’s no way a dog should be allowed into a hospital,’ she says, her voice tight.

‘It’s OK, I promise. He’s been assessed by the therapy-dog charity to make sure he’s got the right temperament,’ I say.

Casey rolls her eyes. ‘I’m talking about germs! People here are sick already, and animals carry horrible diseases that could make them worse. Or cause allergies. Or even zoonoses – that’s illnesses that cross the species barrier.’

Whoa! Who has filled her head with these scary ideas? I stay calm as I reassure her. ‘Well, the doctors love it when we come in, and we have very strict rules. We stay away from vulnerable patients, and Bear always has a bath before he comes, even though he hates it.’

But her stern expression hasn’t changed.

Jed stands up, arms relaxed, all open body language, to diffuse the conflict. ‘Tell you what, Casey, you could go and see the play therapists down the corridor? You could make something, or paint your new treatment mask, just while Bear is here.’

Casey tuts. ‘I’m twelve, not two. You can’t fob me off with poster paints, or building a dinosaur out of egg boxes.’

‘We’re all out of egg boxes. But we do have a top-of-the-range Mac next door, if you fancy making an animation or recording a vlog?’

Her eyes dart to the right. ‘I guess,’ she says, trying not to sound interested. Jed always seems to find a way to relate to the pupils who come here, whether they’re a scared tween like Casey or a tiny child learning their alphabet in between surgery or chemo sessions.

Jed’s pretty good with adults too. Volunteering here was his idea. He’d been reading about the benefits of therapy dogs, and Bear has loved people since I adopted him. It took almost six months to get through the volunteer red tape, but interacting with these kids has calmed Bear down and stopped me from retreating completely into my little nest of sorrow.

‘Can I read him a story?’ the brown-eyed boy asks.

‘I’m going to brush his hair,’ the girl with pigtails announces in a cute Welsh accent. Kids come from all over the UK for treatment at the unit. ‘You always have to brush your hair before going to school, and his is a right mess!’

‘He’d like that,’ I say, removing his red Assistance Dog tunic and taking his brush out of my bag. Bear hates being groomed by me, but accepts it stoically here.

As he settles down with a tremendous sigh, the boy starts to read a story about wizards storming a castle. I glimpse Casey through the glass window into the art room. I’ve never seen any of the kids look quite that lonely.

When school finishes, she shrugs off Jed’s offer to show her where to find Scanning and Diagnostics for her next appointment. ‘I can read signs. I’ll work it out on my own.’