‘Oh Craig,’ she said, and reached out for his shoulder. There was a chorus of sympathetic noises from the other officers.

‘Well, let’s keep going to be sure,’ Gillard said, squeezing his eyes shut, and fighting to control his emotions. Sam can’t be dead, she simply can’t be.

On the other side of the car Tunnicliffe levered off a huge lump of ice, and said: ‘They can do miracles now with hypothermia, sir.’

Gillard made a fist of his now-frozen hand and it created a crack above her face, which with his other hand he pulled at. A dinner-plate-sized wedge cracked, and the face was revealed.

Not Sam. Someone he didn’t recognise. ‘It’s not her!’ he yelled.

‘Who is she?’ Otara asked.

‘I don’t know, another victim I suppose. But definitely not Sam.’

There was a rattle and a splosh. ‘Where was that from?’ Hoskins asked.

Claire looked at him, and then at Gillard. ‘It didn’t sound like it was from the car.’

Gillard stared in at the body emerging from the ice. He pulled back, and stepped away from the car, a glazed look across his face.

‘Oh God, now I understand.’

Drowned by your own hand.

‘We’ve got to move this car,’ Gillard shouted.

‘Why?’ Tunnicliffe asked.

‘Because he’s buried Sam in the inspection chamber underneath and we’re drowning her in the meltwater,’ he replied.

‘It’s impossible,’ Hoskins said. ‘We can’t roll it. Everything round the handbrake is frozen solid.’

‘There’s a dozen of us, we could try bouncing it,’ Tunnicliffe said.

They all gathered around the vehicle, needing only to move it three or four feet to the left. Tunnicliffe, a massive man built like a power lifter, got a careful grip under the front of the vehicle. They all heaved, but with the additional weight of the ice inside, on top of the 1.7 tonne basic weight of the Warrior, it was beyond them. With the hot air blowers going full pelt they were soon sweating. They didn’t have time to keep doing it this way.

‘Give me the blowtorch,’ Gillard said. He crawled under the vehicle and was immediately drenched by the pouring meltwater. He quickly found the hydraulic brake cable, melted the ice and burnt through it. Sliding out, he said: ‘Quick, push it further forward towards the exit. Let’s hope it’s not in gear.’

Sure enough, with Tunnicliffe’s help, they were able to edge the vehicle forward enough for Gillard to get to the metal plate locked over the inspection chamber. There was a bang, and a splash, then another bang. It was definitely coming from the pit in the concrete. The locksmith, lying side-by-side with the detective, worked away on the padlock. It took a full minute, but seemed like an hour. Once it was freed, Gillard pulled back the two metal plates, to discover the pit was already almost full to the brim. A coffin-sized metal locker was floating, its top just two inches above the surface of the water.

‘Sam, are you in there? Give me a kick.’