Sarah had come off the phone and read to Len Gibbons the dishes on the takeaway menu from the trattoria at the top of Haymarket. Beyond the drawn blinds, the evening had closed quickly and he thought the central heating in the suite needed a tweak – there might be a frost before morning. He was on expenses and there was a quite generous allowance for evening meals on duty, but he had never been one to abuse a system’s finances. Just a pasta dish with some chicken and tomato sauce, a bottle of Italian mineral water and… The matter of the Engineer had seemed to be stymied, and the momentum had seemed to have died.

He had not made the presentation, but had sat silently on a hard chair in the corner while men and women of greater rank did the talking. His own section head had read verbatim from Len Gibbons’s brief. The great and the good, two weeks and a day before, had cringed.

‘What – go on to Iranian territory? State-sponsored terrorism, by us, inside Iran’s frontiers? Ask our Special Forces to violate that hornets’ nest? They’d be entitled to refuse point blank. It would be an act of war, and the consequences of failure too awful to consider. I couldn’t urge my minister to permit this action, however much of our blood is on this reptile’s hands. Out of the question even to consider assassinating an Iranian on his own territory. Simply not possible.’

But a woman from the Foreign and Commonwealth office rapped her pencil on the table for attention. She did liaison between the Towers and government, had grey hair styled close to her skull, a lined face and wore a blouse that some might have described as stuffy with jewellery that had probably come from a grandmother. Len Gibbons noticed her beacon eyes, jutting jaw and narrowed lips. She spoke rather quietly: ‘Any former students of ancient history here done Mesopotamia? No? Well, there was a king of Babylon, Hammurabi, powerful enough to have left a Code behind him, written in Akkadian.