spring would create a spark, which would ignite a small gunpowder charge. This in turn would detonate the twenty-four sticks of gelignite.
Unlike a clockwork detonator, which is bulky and makes a ticking noise, the acid detonator was silent. However, whereas a good clockwork detonator can be set to explode within a five-minute window, acid detonators are only accurate to within thirty per cent. So the bomb was likely to go off in somewhere between two and four hours.
Henderson put the lids back on the two boxes and slid them on to a high shelf. Then he left army headquarters for the last time.
13:44 Boulogne
Marc felt weird, squatting on the warehouse floor, knowing that the two dead Germans and the rags they’d used to clean up their blood were squeezed into the tar drums beside him. He opened the canvas bag and pulled out a sketch drawn by Paul, before explaining to Khinde and Rufus.
‘This drawing shows the port,’ Marc explained. ‘One big harbour, one even bigger harbour and the canal system behind it. Right where the canal meets the harbours is the coal yard and, most importantly, these two large tanks for boats that run on diesel. If we can blow those tanks, we can get an explosion going that lights up the sky. The only problem is that fuel burns fast, so we need these.’
Marc pulled a grenade-sized package out of the bag and handed it to Rufus.
‘Phosphorous bombs,’ Marc explained. ‘These explode into fragments that burn white hot for up to half an hour and set light to anything they come into contact with.’
Marc pulled something that looked like a block of marzipan out of the bag. ‘This is plastic explosive. Powerful, sticky, and you can mould it to any shape you like. What we have to do is get up into the fuel yard and drop a bunch of these phosphorous bombs into the fuel tank. At around eight-thirty tonight we go back to the fuel tanks and stick a lump of this plastic to the side of each canister, we light a two-minute fuse, then run like hell, and drive away in Kuefer’s Mercedes.’
‘They’ll miss us before then,’ Khinde said. ‘The Germans will search.’
Marc shook his head. ‘Kuefer’s moody, nobody wants to upset him. If I say Kuefer’s taken you two on some special assignment nobody is going to care enough to ask any more questions.’
‘What about getting through the perimeter security?’ Rufus asked.
‘Everyone knows Kuefer’s car. Nobody ever stops us.’
‘Sounds like you’ve thought of everything.’ Khinde smiled.
Marc shook his head. ‘Not me. Henderson came down here the Sunday before last and scouted the whole place. All I’m doing is following his instructions.’
‘So what now?’ Khinde asked.
‘I’ve got Kuefer’s camera and a fifty-metre rule so that you guys can pretend to take measurements.’
Marc hooked the Leica camera around his neck, grabbed the bag and walked several hundred metres, passing the huge open-sided coal shed. A small crew worked in the shed repairing a narrow-gauge steam train that distributed coal around the docks, but nobody took any notice as Marc stepped up to the diesel tanks and began taking photographs, while Khinde and Rufus held opposite ends of the measuring tape.
Marc was climbing up a ladder on to the top of the tank when he saw Louis, the head draftsman and engineer, heading towards them.
‘Where’s your boss?’ Louis asked angrily. ‘I saw his car, but I’ve been waiting for him in the office like a goddamn turkey for forty minutes.’
‘I’ve got no idea,’ Marc said. ‘Something weird’s going on. I met him up by the gate, but he drove off in another car with some black uniforms inside.’
‘The SS?’ Louis said warily. ‘What do they want with Kuefer?’
Marc shrugged and acted irritated. ‘Why do you people think know everything? The boss tells me to get two labourers, then come out here and measure these tanks, then wait for him to come back. He says it might be a few hours.’I
‘The Germans only installed those tanks a few weeks back,’ Louis said. ‘I wonder what they’re playing at now.’
Marc pointed at Rufus and Khinde. ‘And these two guys are worried that they’ll be missed down at the yard. Can you make sure everyone knows they’re working for Kuefer?’
‘Sure,’ Louis said. ‘If Kuefer comes back, tell him I need to see him. I’ve got three docks sitting still, waiting for his approval on revised drawings. And I don’t know why he’s got you taking measurements and pictures. The Germans