‘But you might be able to get in through an upstairs window. And I know Courtney has a cellar. There might be a hatch of some sort for it round there.’

Sure enough, Mwangi spotted the bathroom window and the drain that ran down from it to the ground. There was no light coming from the window, which was shut. There had been no reaction from the bathroom to their presence below it. Mwangi concluded there was no one behind the window.

But the window wasn’t the only thing that had caught his eye in the moonlight. At ground level there was a long, flat piece of wood, set in a frame to which it was secured by a hefty padlock.

Mwangi had never lived or worked in a building that had a basement. Had it not been for De Lancey’s suggestion, he would not have known that he was looking at a hatch. But now he looked closer and saw two sets of hinges on the side of the frame closest to the house. There was also a metal hook attached to the wood and a catch on the wall. So the wood lifted up on the hinges and was then hooked onto the wall.

But first he had to deal with the padlock.

Mwangi told one of his men to stay with him. He told the other four to climb up the drain, go into the house through the bathroom window and sweep the top floor of the house.

‘If you find bwanas and memsahibs, kill them all,’ he said. ‘Then go down the stairs and join our comrades in the fight.’

Next Mwangi turned his attention to the basement hatch. He blew the padlock to pieces with a quick burst from his Sten, though the sound of his firing was lost in the din from the rest of the building. He lifted up the hatch, which was a single piece of solid wood and surprisingly heavy, and ordered his sidekick, who went by the name of Roosevelt, to secure it to the wall.

The hatch opened to reveal a steep brick staircase descending into the darkness. Mwangi did not like the look of that. But he could not show fear in front of a man he was leading, so he affected an air of stern determination and headed down the stairs with one hand on his gun and the other stretched out ahead of him to guide the way.

Unable to see a thing, Mwangi kept his hand brushing against the brick wall that ran beside the staircase. He hit something protruding from the wall: a light switch.

Mwangi turned on the lights. He saw an arch at the bottom of the stair, facing into the house. It opened onto a broad passage with a flagstone floor with storage bays on either side. One served as a coal bunker, a second was piled with firewood, a third was packed with old pieces of furniture and wooden tea chests.