‘Seriously, Dan, let me in or I’ll buzz all the flats in the building until someone else does.’

I press the button and pull an apologetic face at Casey. ‘You could put your wig back on,’ I suggest, once the camera shows Angelica is safely inside the lobby.

‘She’ll panic and think my hair’s fallen out again.’

‘Can you wash it out now?’

‘I’ve already tried a few times and it looks exactly the same.’

‘OK . . . How about we tell her you had booked in for some kind of deep-conditioning treatment and it went wrong?’

‘That’d make her even more paranoid about chemicals and I’ll never be allowed near a hairdresser again. Plus, I don’t want to lie to my mum.’

‘Then blame me. Say I encouraged you. It won’t change how she feels about me.’ Being the fall guy seems like the least-worst option.

‘I want you to get on with each other, for my sake. So you’re like grown-ups are meant to be. Grown up?’ The hint of sarcasm in Casey’s voice reassures me she will be OK, however bad a telling-off she gets from her mum.

Which is just as well, because the lift has arrived on our floor.

‘Mummy!’ Casey flies into her arms the second the doors slide apart. They hold each other so tightly and I get this brief, guilty flashback to kissing Gemma in that same space only three days ago.

‘My lovely, lovely girl . . .’ Angelica’s eyes are shut as she rests her head on her daughter’s shoulder. Taking time out has done her good. She’s more like the young woman I met at Glastonbury thirteen years ago.

Her eyes snap open.

She clocks the pink colour and rears back so forcefully that I wonder if she’s given herself whiplash.

‘What the hell have you done to your hair?’

Casey cowers and I turn to Angelica, ready to tell her to calm down. But I can see the fear in her eyes now, and my own stupidity hits me. What was I thinking when I let Casey get her hair dyed? It’s a slap in the face for Angelica, after she’s tried so hard to keep our daughter safe.

Why was I too stubborn to see that before now?

‘The colour is ninety-nine per cent organic,’ Casey whispers. ‘And I totally love it.’

‘I don’t care if it’s made from unicorn horn and cockerpoo-puppy breath, I told you not to get your hair coloured and you disobeyed me.’ Angelica’s voice rises as she’s winding herself up more and more. Her eyes lock onto me. ‘As for you. How could you let her do this? You’ve been a parent for all of three weeks and you think you know better than I do. You think it’s OK to go behind my back, defy my wishes?’

‘No, I don’t. Look, Angelica, I should have—’

But Casey interrupts me. ‘Mum! Stop being so mean all the time. Dad is trying his best.’