When he called at the house, Paul fully expected to be sent on his way. To his amazement, he was invited in. It was almost as if his arrival had been foreseen. He was ushered into the drawing room where Oswald Ferriday was ensconced in a leather armchair.

‘I had a feeling that you’d show up again, Mr Skillen,’ he said. ‘How did you get hold of my private address?’

‘I’m used to finding things I regard as important, sir.’

‘Evidently,’ said Ferriday. ‘I saw you briefly at the Home Office. You looked as if you had no idea who I was.’

‘I’ll think you’ll find that it was my twin brother, Peter, who went to see the Home Secretary. He worked as one of his agents in France.’

Ferriday was surprised. ‘There are two of you?’

‘Yes, and we’re both engaged in this enterprise.’

‘So your brother was one of those brave men who worked behind enemy lines, was he? I’m impressed. Espionage is an important tool of government.’

‘Is that why innocent members of Hampden Clubs are under surveillance?’

‘I’ll ignore that jibe and suggest that you sit down.’ Paul settled into a chair opposite him. ‘Now, please don’t abuse my hospitality.’

Ferriday was a middle-aged man who looked much older than his years. Time had twisted his body out of shape and given him a pronounced hump. His face was colourless and criss-crossed with deep lines. His voice, however, was crisp and his gaze searching.

‘I’m sorry that I shrugged you off earlier,’ he said. ‘Sir Marcus Brough scolded me for doing so. We may have fought against everything Sir Roger stood for but, in spite of that, we had a sneaking fondness for him. And we certainly want his killer brought to justice very quickly.’

‘It will take more than a few pious words to achieve that end.’

Ferriday was stung. ‘Do you doubt my sincerity?’

‘I’ve seen no sign of it so far, sir.’

‘Then what would you have me do?’

‘Cooperation with me and my brother would be a good place to start,’ said Paul, ‘and you’ve so far treated me like a leper.’

‘That was a mistake for which I’ve already apologised.’

‘It was only because Sir Marcus chided you. Without his intervention, you’d have kept me at arm’s length indefinitely.’

‘Listen, Mr Skillen,’ said the other, controlling his irritation, ‘I’ve agreed to speak to you even though I’m under no obligation to do so. If you have any questions for me, please ask them but don’t you dare badger me.’

‘I’ll do my best not to do so.’

‘Thank you.’

‘May I ask if you know a man named Hugh Denley?’

‘He’s not a close friend of mine, if that’s what you mean.’

‘But you are aware of who he is.’