‘General Franco,’ said Miles. ‘He built this hideaway in 1937, at the height of the civil war. Even his closest confidants didn’t know it existed. I’ve had to make some modifications,’ he added. ‘Which will prove my point. When you were picked up by the golf buggy, how long did it take you to reach the house?’

Booth Watson thought for a moment, before saying, ‘Six or seven minutes. But a police motorbike would be a lot quicker.’

‘Agreed. And how long did it take us to walk from the drawing room to this study?’

‘A minute, a minute and a half at most.’

‘I can assure you, BW, that anyone who sets foot on my land uninvited – and don’t forget that this house is surrounded by a thick forest – would immediately set off an alarm. Even if they turned up in the middle of the night and I was fast asleep in my bedroom on the first floor, it would still take me less than three minutes to disappear into thin air.’

‘Even if you had your helicopter waiting for you on the roof, I don’t think they’d hesitate to shoot it down.’

‘I wouldn’t be heading for the roof,’ said Miles. ‘The helicopter is there simply to distract them.’

Twelve o’clock struck and a shrill alarm drowned out their conversation.

‘Rehearsal time!’ shouted Miles, as he got up from behind his desk and walked over to a vast iron door embedded in the wall. It had no handle, no lock and, as far as Booth Watson could see, no way of opening it. Miles tapped the face of his watch and waited for it to light up before entering an eight-digit code. Booth Watson watched, mesmerized, as the door swung open to reveal a large, empty space.

Miles stepped inside and beckoned Booth Watson to follow, while the deafening sound of the alarm continued. Booth Watson reluctantly obeyed, and Miles pulled the door shut, leaving them in complete darkness. He tapped his watch again and entered another eight-digit code. A moment later a second door on the far side of the safe swung open to reveal a well-lit staircase.

Miles stood aside to allow Booth Watson to step out. Miles then joined him at the top of the staircase and slammed the heavy metal door behind them.

‘As you can see, BW,’ he said, ‘even if Chief Inspector Warwick and his plodders made it as far as my study, it would take them at least seven minutes, and they would still need my watch and the eight-digit code before they could open even the first door, let alone the second.’

Miles led his guest down the stairs into the basement.

When they reached the study, Booth Watson couldn’t miss that the room was identical to the one on the ground floor above it, except that Franco had been replaced by a full-length portrait of Miles. The other half of Miles’s art collection was also displayed on the walls – Christina’s half.