Then, last Friday evening, behind a shiny red door in the Clarendon, after everyone had left for the Magdalen Arms to toast Professor Whitton’s Fellowship to the Australian Academy of Science, Marvar took a pellet of frozen deuterium contained in a thin shell of plastic, and placed it inside his laser. The icy outer surface of this central pellet was one spherical mirror; the outer edge of the blanket was the other mirror, forming the laser cavity.

‘Not crazy, it just required exquisite alignment between the two.’

‘How did you support the pellet – if it needed to be dead in the centre?’

‘Excellent question!’

Whitton and Cubbage in their experiments used a tube five microns in diameter – ‘but that still causes very noticeable perturbations to the symmetry.’ Marvar’s solution: magnetic levitation.

He looked up. Dyer was flailing again.

‘Let’s not go into that now. Let me tell you what happened.’

Shortly after 7.30 p.m. Marvar stepped back from the target chamber behind a lead-lined concrete wall, slipped a pair of safety goggles over his eyes, and switched on the power supply. Through the bright green lenses, he watched multiple laser pulses launch shock waves into the pellet, sending waves that rocked back and forth, back and forth, getting stronger and stronger, like the waves that Samir used to slosh in his bath – ‘his mother hated it!’ – until all at once the lasing atoms broke through, ‘creating a pulse of beautiful, spherical light’.

It was not a sustained reaction; it lasted until the fuel was burned up – this carefully calculated by Marvar in order for him to survive the high-density implosion. In a molten hurry before any of the team returned, Marvar then measured the size of the reaction with the Clarendon’s time-gated X-ray camera, the burn duration with the X-ray streak camera, and the neutron yield with the lab’s new neutron activation detector. He scarcely dared breathe the result.

He drew himself up and looked fully at Dyer.

‘I had not just good compression, it was better than that. I had perfect compression. When I checked the data, I had created more energy than I had used.’

Marvar said, blazing: ‘I had got the conditions for fusion using a machine no bigger than Samir’s football on the space of your kitchen table.’

Chapter Twelve

MARVAR TURNED AWAY. IN HIS coat, he stood on the bank and stared at the trees. An excursion boat was roped to the far side, chairs stacked up on deck. A young woman’s muted laughter came from the bridge.

Dyer opened his mouth and he forgot what he was going to say. It was incredible what Marvar had told him. If true, the implications were immense for everyone, for all time.

But was it true?