‘We’d better get out of the way, leave them to it,’ said Charles. He and Gareth slipped out into the corridor away from the balcony. The first office on the left was unlocked and empty. From the window they could look across to the two Land Rovers parked outside the entrance, their doors open but no one visible.

Gareth locked the door. ‘Presumably you’re a prime target, if they recognise you.’

‘Just as well I’m not in my office.’

‘Would they know which it is?’

‘Probably not.’

The alarm stopped clanging, though in the silence that followed seemed to go on ringing. There was what sounded like heavy breathing in the microphone. A woman’s voice said, ‘Intruders . . . intruders . . . intruders on first floor east wing. Staff in east wing must . . . all other staff must evacuate by staircase number one west.’ The alarm resumed, then stopped again. A man’s voice said, ‘Response team due in three minutes repeat three minutes. Remain in your offices and lock your doors. Repeat remain—’ His voice became strangulated and the microphone made a noise as if it had been banged against something. In the park outside four Range Rovers raced up the drive from the main gate. Like the Land Rovers, they bumped up the steps and disgorged armed men, also in black but helmeted and wearing flak jackets signifying that they were police. There was more shooting.

Charles was looking out of the window. ‘One of them’s fallen over. That was his gun going off.’

Gareth leaned against the desk, smiling, his arms folded. ‘Great. Boys in blue doing their usual stuff. And the control room helpfully broadcasting to the attackers where they are, where everyone else is going and when the cavalry’s coming. Worth doing, don’t you think? Confirms what we suspected: bloody chaos.’

‘Lessons learned?’

‘Apart from all that, no adequate defences against unauthorised vehicles getting close, possibly packed with explosive. Security booth reinforced glass easily broken. No adequate second barrier once they’re through it. Control room all over the place, as we saw, despite being warned to expect it. And that’s just what we witnessed. Another twenty minutes till final whistle, so there’ll be plenty more.’