‘So was I,’ admitted Paul. ‘Political life may be full of intrigue and vaulting ambition but even the most impassioned individuals would stop short of plotting someone’s death. While there may be occasional duels between political enemies, I know of no examples of outright murder.’

‘Sir Roger felt that he was in jeopardy.’

‘Then why didn’t he travel with a bodyguard?’

‘He poured scorn on the notion,’ said Kitty, ‘and, with a sword in his hand, was well able to defend himself. My husband discovered that.’

‘Were any other enemies named by Sir Roger?’

‘No,’ replied Kitty, ‘only the Doctor.’

‘He was called that because his father was a notable physician. It’s hardly an appropriate nickname, is it? Doctors are supposed to save lives. They follow in the footsteps of Hippocrates and seek to cure. Primum non nocere is a phrase I learnt at school – “First, do no harm”. If the Home Secretary is involved, then he’s in direct contravention of medical ethics.’

‘I never thought of that.’

Although she’d been conducting an affair with one man while married to another, Kitty Denley had a strange innocence about her. Paul could see how someone like Mellanby had been attracted to such a woman. It was not only her beauty that had captivated him. He’d also been drawn by her patent honesty and her desire to lead a very private life. Since some of it would be shared with him, he’d found her irresistible. For her part, she’d been in love for the first time and waited patiently for his occasional visits to brighten her otherwise lonely existence.

Putting her head at an angle, she stared at him with interest.

‘You’re a brave man, Mr Skillen.’

‘I’m simply one who believes in justice.’

‘Sir Roger often said that.’

‘Then he and I have a bond.’

‘I’m truly worried for your safety.’

‘There’s no need,’ said Paul. ‘I’ve been in danger before. You might say that it’s my natural habitat. Have no fears on my account.’

‘If you were there when it happened, it must have been frightening.’

‘It took me by surprise, perhaps, but I felt no alarm. I was simply left with this urge to catch the men responsible and haul them into a court of law.’

‘You could never do that to the Home Secretary.’

‘We don’t know that he was definitely a party to the murder.’

‘That’s true.’

‘So let’s not condemn him without first getting clear evidence.’

‘How could you possibly do that?’ she asked, hopelessly. ‘You’d never be allowed to get anywhere near the Doctor.’

‘Maybe not,’ said Paul with a smile, ‘but I do know someone who does have privileged access to him. In fact, I know him extremely well.’