"They blew the bridge because the point where it meets the bank is their weakest spot," said Ferguson.
I panned across with my binoculars to focus on the jagged outcrop of stone that marked the opposite side of the now destroyed Westminster Bridge. I could see immediately what he meant. At the foot of Big Ben there was a patch of open ground between the wall of the Palace and the edge of the bridge accommodating some steps that led down to a tunnel entrance. The tall black fence that ringed the Palace only came up as high as the bridge, which meant that you could get inside by laying a plank of wood across the gap and leaping in. Obviously not an option when the CCTV systems were all working, but now it seemed eminently doable.
"It's called Speaker's Green," explained Ferguson.
"What's that tunnel entrance?" asked Jack.
"Westminster Tube. There are tunnels direct from the station into the Palace and that big building opposite it, the one with the black chimneys. That's Portcullis House where the MPs offices used to be. There's a tunnel running from there under the road into the Palace as well."
"In which case we should go in underground, through the tube," I said. "They blew the bridge but they didn't blow the tunnels, did they?"
"They didn't need to," the Ranger replied. "Once the pumps shut down, the tube tunnels all flooded. The old rivers that run under the city reclaimed them. If we had scuba gear, maybe, but even then it'd be madness."
"So we go in over the fence there?" asked Jack.
"It's an option, but it's the wrong end of the building," said Ferguson. "If we go in there we have to travel the whole length of the Palace to get where we're going, which massively increases our chances of discovery. No, our best way in is there. The Lords Library."
He pointed to the opposite end of the Palace, to the huge tower that marked its southernmost point.
"There are only two places where the Palace backs directly onto the river, and that's the towers at either end," he explained. "In between there's a bloody great terrace between the wall and the river. What we have to do is get on the water, moor at the foot of that tower, and climb in one of the windows. It's our best way of getting in undetected."
"I don't know about you, mate, but I'm not Spider-Man," I said. "There's no way in hell I'm going to be able to scale that wall."
"What we need," said Jack, "Is one of those grappling hook gun thingys that Batman uses."
"Nah," said Ferguson, smiling. "We can do better than that."
Ten minutes later we climbed down from our vantage point through the ruined interior of St Thomas' Hospital, emerged into a street buried under a thickening carpet of snow, and set off in search of a dinghy.
"Whatever you do, don't fall in, okay?" said Ferguson unnecessarily as we climbed into the small inflatable that we'd found in a River Police station half a mile upstream. "The water is freezing and the current is deadly. If you hit the water you're dead, simple as."
"But we're wearing life jackets," I pointed out.
"Don't matter," says the Irishman. "You probably won't be strong enough to swim to the shore. You'll stay afloat, but you'll freeze to death before you hit land."
"I thought Irish people were cheery, optimistic types," said Jack as he climbed carefully into the rubber boat.
"What the fuck ever gave you that idea?" asked the Ranger, untethering the boat and pushing us away from the shore.
"Um, Terry Wogan?"
Ferguson clipped his ear and handed him an oar. "Row, you cheeky sod."
There was no moon, but the world was clothed in white and the sky was still thick with falling snow. The current took us quickly and we floated out into the Thames.
"We can't use the engine, 'cause they'll hear us," explained Ferguson. "And we don't have an anchor, so the hardest thing will be to bring ourselves to a halt long enough to climb out. When I give the signal, you two need to start rowing as hard as you can against the current. Got that?"
Jack and I nodded as Ferguson used his oar to steer us as close to the bank as possible. Although the blizzard was providing us with the best possible cover, there was no point in taking foolish chances; the further out we were, the easier we would be to spot.
I was astonished at how fast we moved, and we were floating alongside Parliament within ten minutes. As we neared the farthest tower, Ferguson gave the signal. Jack and I dipped our oars and began paddling frantically against the tide, trying to slow us down. The Ranger took his bow and notched an arrow. Attached to the shaft was a small metal grappling hook from which trailed a slender nylon rope. Despite all our efforts, we continued to sweep down the river, but Ferguson did not allow himself to be distracted. As we reached the tower he let the arrow fly. It soared away into the white and although we listened, we never heard it land. But the rope didn't tumble back to the water.
He grabbed the end of the rope and looped it through one of the metal rings on the rim of the dinghy and pulled. I sighed with relief as the rope went taut and he pulled us in to the edge of the river, where the dinghy nestled underneath the concrete lip that marked the ground floor of the Palace. He tied it off and Jack and I gasped with relief as we dropped our oars. My arms were burning from the effort of rowing against a current that laughed at my exertions.
We looked up at the blue nylon rope that trailed up into the night sky. The snow was so thick now that the top of the tower was lost to view. The rope seemed to rise up into nowhere. We all pulled on the rubber-coated climbing gloves that Ferguson had looted for us from a sports store on our way into town, and put on the strange climbing pumps which were soft and lacked soles, but had rubber moulding all over, for purchase.
"Climbing in these conditions is extremely dangerous," said Ferguson. "So we'll go in the first window we come to. Take your time, don't hurry, and remember — there's no safety rope, so whatever you do, don't lose your grip."
I handed him the heavy kit bag that was the key to our success. He slung it over his back, took the rope in both hands and launched himself off the dinghy. He scrambled up over the concrete lip in no time at all. We waited until we heard a muffled crack and saw shards of stained glass tumble past us into the water. I gestured for Jack to go first.
He nervously followed Ferguson, but whereas the Irishman had been speedy and confident, Jack was all over the shop. His prosthesis slowed him down, and his fibreglass foot scrabbled uselessly against the wet concrete and he slipped backwards more than once as the nylon rope got wetter and more slippery. Eventually he also disappeared over the concrete lip and the rope went slack indicating that he'd made it inside.
I grabbed the rope and pulled myself up. Every set fracture and old bullet wound protested as I hauled myself skywards, but I focused on doing everything slowly and carefully, and managed a steady, unwavering ascent.
When I crested the concrete rim I saw a gothic arched hole where a stained glass window had nestled. I reached up to grab the window sill and two things happened in quick succession: there was a burst of gunfire from inside the room, and Jack crashed out of the window to my right, flying backwards in a cloud of glass and lead, clutching Ferguson's black kit bag, plummeting soundlessly into snowfall.
I braced my feet against the stone, looped the rope around my left hand, reached into my coat, pulled out my Browning and then pushed up with my legs, propelling my head and shoulders in through the gaping stone window frame, firing as I went.