The porter comes out of the lodge and raises the security barrier as Stacey pulls into the driveway.

‘Hi, Fredo,’ Stacey says. ‘You look like you’ve caught the sun.’

‘Welcome back, Mrs Porter. Nice day to be on the courts.’

‘It’s yoga this morning,’ Stacey says. ‘But we might stay and have some lunch afterwards, as it’s such a lovely day. This is Millie Downton, a friend of mine.’

‘Nice to meet you, Ms Downton. I’ll phone ahead for you, Mrs Porter, and reserve a table.’

I’ve never had a female friend before. I didn’t want one: Tom was always enough for me. I’ve never really understood the mysterious and strange nature of female friendship: the emotional intimacy and need to share the innermost details of each other’s lives which from the outside seem to make the relationships as fraught as they are gratifying. It’s a common trope that men are more competitive than women, but in my experience women are simply competitive in a way that’s less obvious – they’re competitive about connection.

The girls I knew at college, the women I worked with at the hospital: what appeared to matter to them most was the degree to which they were privy to each other’s secrets. And I was always too ashamed to share mine.

Stacey noses her car around a group of women in tennis whites walking three abreast and follows the gentle sweep of the drive towards the Georgian clubhouse. Sitting beside the Thames in Fulham in forty-two rural acres surrounded by the stressful clamour of central London, the Hurlingham Club is an anachronistic survivor of a different age. It lost its polo grounds after the Second World War when the London County Council nabbed them by compulsory purchase for council housing, but it’s somehow managed to hold off all-comers since then. The goalposts of the so-called class war may have shifted, but the Hurlingham is still an unapologetic oasis of privilege.

‘How long have you been a member here?’ I ask as she parks behind the clubhouse.

‘All my life. My parents were members, though we didn’t come here much after they moved back to Norfolk when I was about seven.’

Tom and I have been on the waiting list for nineteen years, ever since we first moved to London when I was a medical student at Guy’s Hospital. Actually, we’re still waiting to get onto the waiting list proper, which is currently closed: the only way to become a member is to be born to someone who has membership, and then wait for them to die. Full membership is the holy grail.

‘Do your parents still live in Norfolk?’ I ask.