‘Rome was under attack,’ said Lingoss. ‘The army had lost the Battle of the Allia and needed to get a message into Rome, which was besieged at the time, and so a soldier named Pontius Cominus floated himself down the Tiber. Roman mail shirts weighed around thirty-five pounds. Some say he made a cork float. Some say he fashioned a cork life jacket. Some say he sewed cork strips into his armour. That’s what we’re trying out now.’ She grinned wickedly. ‘You’re lucky you didn’t come tomorrow.’

‘Why?’

‘Some reports say he used an inflated sheep’s stomach. We have half a dozen being delivered tomorrow.’

‘Sheep?’

‘Oh, good heavens, no. Just the stomachs. We’re still working on methods of inflating them. They rupture very easily.’

R&D shook its collective head at this massive flaw in sheep design.

The professor was examining the armour. ‘It would appear the cork strips are not sufficient, Miss Lingoss. All they do is cause him to sink more slowly. I’m thinking of tying more cork to his boots. Roman sandals were quite substantial so this would keep his other end afloat as well.’

The obliging Bashford sat quietly while his feet were enveloped in cork. Not something on everyone’s job description.

‘Can someone pass me my pen,’ said Lingoss, suddenly. She wrote busily on Bashford’s feet for a minute then pushed the pen into her hair where two or three of its fellows already resided. ‘Ready when you are, professor.’

‘In your own time then, Mr Bashford. I’m very hopeful this will be successful.’

Bashford passed Angus to Matthew. ‘Can you hold her for a bit? She likes to feel involved. I think she enjoys it,’ he said, hobbling awkwardly in his new platform soles. ‘She sleeps a lot now, of course.’

‘She slept a lot before,’ said Lingoss.

‘Well, yes, but now we treat her gently and try not to give her any shocks.’ He lowered himself into the pool. ‘This water’s freezing.’

‘So was the Tiber. We need everything to be as accurate as possible. So – in your own time, please.’

‘Right,’ said Bashford, letting go. ‘I’m floating down the Tiber now.’

Oh no, he wasn’t.

Later, Jane would find it hard to describe what happened next. Slowly and gracefully, Bashford upended himself, his upper torso sinking beneath the surface but his feet slowly rising above it. As she said afterwards, it was quite balletic. Within ten seconds, the only part of Bashford still above the Tiber was his feet. To be more accurate – the soles of his feet, bobbing authentically.

People stared. ‘What’s he doing?’

Lingoss gave a shout. ‘His feet are more buoyant than his head. They’re pushing his head down into the water.’

‘Interesting,’ said one of the team. ‘Do you think there’s some sort of buoyancy ratio? Feet to head?’