‘I’ll do it,’ snapped Porter, through gritted teeth.

He closed his eyes, took a deep breath, and ignored the pain still aching through him from where he’d been operated on the day before. Tossing the rope back, he swung it over his head, and concentrated. One jump, and he was over. He swung the rope again, following its arc as it cut through the air. Over. Just get the rhythm, he reminded himself. Then it’s easy.

‘Ten minutes,’ said Sam. ‘Then we’ll play with some real toys.’

By the time the skipping was completed, Porter could feel the sweat pouring off him. His shirt was wet through, and his skin felt sticky and clammy. He took the bottle of mineral water Sam offered him, and swigged it back in a couple of gulps. ‘Let’s start the fun stuff,’ said Sam.

The swing of his fist caught Porter by surprise. Sam’s arm flung back, then smashed into the side of Porter’s face. The palm of his hand hit his cheek, stinging the skin. Instinctively, Porter lashed out, thrusting a clenched fist forward, but Sam had already danced out of the way, and Porter was left flailing in thin air. His lungs were gasping for air, and he was still trying to recover his breath when Sam grabbed his right arm, and swung it viciously upwards. Porter gasped with pain as Sam slowly increased the pressure on the arm. He could feel the tendons starting to stretch, and his eyes started to water. ‘You’ve got to be faster than that, mate,’ said Sam.

Porter roared, filled his lungs with air, then snapped his right arm down. The pain was screeching through him, as he thrust backwards with his legs, smashing his back straight into Sam. He could feel Sam start to wobble as his groin took the impact of the blow. For a fraction of a second, the grip on his arm weakened. Porter tugged it free. He swung round, struggling to hold on to his balance. Ducking, he put his head down, then threw himself forward, smashing into Sam’s chest with his head. That was a technique he’d learnt on the street, he reflected, as he saw Sam shake under the impact of the strike, then fall back on the ground. When in doubt, headbutt the bastards. You might give yourself brain damage, but, let’s face it, when you were living rough and drinking two bottles of vodka a day, there wasn’t much point in worrying about that.

‘That fast enough for you?’

‘No marks for technique,’ said Sam. ‘But you’re still strong.’

‘Just remember, I was in the Regiment and you weren’t,’ Porter growled.

Sam picked himself up off the ground, and this time it was him drinking half a bottle of water, and struggling to recapture his breath. ‘You need to calm down though. You’re getting riled up too easily. Take your time, figure out your opponent’s weaknesses, then strike.’

Sam led him towards the shooting range. There wasn’t enough room underground for a full-scale range, but there was single block of enclosed concrete with a target at the end of a forty-foot strip. The firing point was just a white line printed on the ground, and next to it, there was black wooden table with a row of about thirty guns laid out on it. From a quick glance, Porter could see they covered the complete range of global arms manufacturers. There were Berettas, Brownings, Mausers, Walthers, Enfields, Webleys, Colts and, of course, Kalashnikovs, as well as a dozen different varieties of Asian and Eastern European knock-offs. ‘What do you want to have a go with?’ said Sam.