‘Fine. Now, show me how you hold the bow. No, that’s completely wrong. You put your thumb under. So. Now you curve your fingers around. Not all stiff; relax them. Like a tunnel. No, relax. Look at that little finger, it’s as stiff as a stick. OK, now just move your arm up and down, holding it like that. And from side to side, like a windscreen wiper. Good.’

Catherine Wattisham lived in a detached house in Islington – one of those houses with French windows giving onto green lawns, huge mirrors hanging over wide fireplaces, a smell of polish and cut flowers in the air. She wasn’t at all what Irene had been expecting. She was an elderly woman with a straight back, a tweed skirt, stiff grey hair in a helmet of rigid curls. But when she picked up her violin and put it under her chin her body became suddenly supple, as if water was flowing through it, and her expression changed. She looked as if she was listening to a sound that was coming from far away and that no one else could hear – like an old sailor on the prow of a ship who knew the song of mermaids. Music rippled from her bow.

‘Hold the violin by its neck – not as if you’re trying to throttle it though. You’re cupping it instead, cradling it. Be subtle, Irene, tender. Remember, those fingers have got to move on the strings. How will you be able to do that if you’re holding onto the neck as if you’re killing a goose? Now put your violin against your shoulder and under the chin, like this. You should be able to take away your hand and balance it. Everything’s got its equilibrium – the bow, the violin, they should feel natural. Don’t clutch so. You have to practise just holding them. Buy a shoulder pad for next week, will you?’

‘Yes.’

‘Can you read music?’

‘Ye-es,’ Irene said doubtfully. She could read music like some of her dyslexic students read words – painstakingly, letter by letter, fitting unwieldy sounds together on their tongues.

‘These strings: G,D,A,E. Yes?’

‘Yes.’

‘Put the heel of your bow on the D and draw it all the way to its tip. Steadily. Don’t move your wrist, move your elbow. Good. Now the A. Yes. Do it on all four strings. Lift your elbow or drop it to get the right position. Whole bow, remember. That’s your homework. That and practising the way you hold your bow and violin.’

‘OK.’ She felt like a schoolgirl.

‘It takes time and work. One day, you’ll find you do it instinctively. Instinct comes with practice.’

‘Adrian.’

‘Mmm.’

‘You have to tell me what’s going on.’

‘Nothing’s going on. I’m tired, that’s all. I’m in the middle of doing a play in case you haven’t noticed.’

‘I know, but …’