‘Show that letter to a single person and I have nothing to lose,’ Lavinia had hissed down the phone the previous day. She never called the house, always the practice. ‘I will make sure every woman in the avenue knows that girl for what she is, do you hear me? It will take me one call to the golf club captain and another to the medical council. The captain always rather liked me, not that you’d have noticed. And don’t you ever forget, the medical council will have to listen to me because she was a patient registered on your list. We all know the price a doctor has to pay for sleeping with one of his own patients, don’t we? Never mind living over the brush with the little whore.’

She gave a shrill laugh that sounded like breaking glass and had the desired effect of sending a shiver down his spine. She was of course quite right. Mary Kate had been his patient.

‘Had even you forgotten that little fact? She was registered on your list at the practice, not Robin’s – at your absolute insistence, he told me. Your patient, not his, and he will testify to that now that his poor wife knows what happened. Ruined everything, you did, Nicholas, because you couldn’t keep your trousers up.’

The phone in his hand shook violently. His throat tightened and his mouth was dry. Fear made it impossible for him to speak, but at that particular jibe he almost laughed out loud. His wife had been having an affair with his partner for months. There had been others, for which he had always forgiven her, but not this time, even though Lavinia now had the power to ruin him and it was all in her hands.

‘You will lose your job, the house, your reputation, your precious patients… And as for that harlot that you insultingly refer to in my presence, the mother of your sons, as the love of your life – you won’t see her for dust. It’ll be all over the newspapers and Mary Kate will be known forever as nothing better than a scarlet woman.’

The first time she’d called and made her threats, he’d driven twice around the park before returning home after work, asking himself over and over, should he tell Mary Kate? He had decided against it. She didn’t need to deal with that, and besides, how could she? She was far too young and trusting, the opposite to Lavinia in so many ways. He would handle Lavinia in secret and shield Mary Kate from her intimidations.

‘Use the letter that Robin wrote to me, that your little harlot stole, and I can tell you this: you will unleash the dogs of war. Neither of you will survive. You have committed the ultimate crime for a doctor, my darling, broken the absolute taboo, brought the Hippocratic oath into disrepute. Not fit to practise on ethical grounds – that’s what they’ll say when it’s reported to the General Medical Council, so Daddy tells me. The only thing you have in your possession, Nicholas, is the ability to prevent me from doing much worse. Try me and I will destroy you both.’