Stuart bit his lip. ‘He went up to Aberdeen. Of course, I can’t be sure whether there was anything going on.’

‘Nobody can be sure about such matters, sir,’ said the police officer. ‘People can be very discreet. Understandably.’ He paused. ‘Was everything all right at home?’

Stuart shrugged. ‘I think so. My wife is not necessarily an easy person. She’s a bit … a bit opinionated. She has strong views.’

It was clear that this interested the police officer. ‘Strong views on what?’

‘On everything, I suppose.’

The policeman nodded. ‘But you hadn’t had a recent row? Nothing that could have made her go off suddenly – without any warning?’

Stuart shook his head. ‘No. Nothing like that.’

The policeman cleared his throat. ‘There’s one other thing, sir. I’m sorry to have to bring this up, but you might know that we have a note in our files about contact between you and a certain Glasgow underworld figure. Could this have any bearing on your wife’s disappearance, do you think?’

Stuart gasped in astonishment. ‘Underworld figure?’ he stuttered.

‘One Aloysius O’Connor,’ said the policeman. ‘More generally known as Lard O’Connor. Now deceased.’

‘But I hardly knew him,’ Stuart protested. ‘I left my car outside his house by mistake. That’s all.’

‘And yet you were observed visiting the Burrell Collection with him,’ said the police officer quietly. ‘Does one go to a gallery with a complete stranger? And you were accompanied on this little cultural outing by one Gerald Sean Flaherty, known to our colleagues in the Strathclyde Police as the Sage of Maryhill, not a man widely believed to be interested in the arts. Yet you all went to this gallery together.’

Stuart looked dazed. ‘I really didn’t know these people,’ he said. ‘And anyway, I don’t see what this has to do with my wife’s disappearance.’

‘It very likely has nothing to do with it at all,’ said the officer. ‘But I’m sure you’ll understand why we have to look into all possible explanations.’ He paused. ‘And I’m afraid, sir, that I am very concerned over this case. You see, women do not normally leave their children – their husbands, yes, but not their children. So this makes me very concerned about your wife’s welfare.’

Stuart looked down at his hands. Of course it had occurred to him that Irene had met some terrible fate, but this was the first time that anybody in officialdom had been prepared to acknowledge that.

The officer spoke gently. ‘So you’ll understand why I must ask this question: did she have any enemies?’

‘Lots.’ Stuart had not intended to answer in this way but the response came spontaneously. ‘She didn’t deserve them, of course, but sometimes she was a bit outspoken. People are rarely ready for that.’

The policeman nodded. ‘Anybody in particular?’