‘And people displaced, again.’ Colin gives Ms Williams no time to answer. ‘As in the 1950s and 60s. Whole communities.’

‘You’re talking about the bombings then, of dams in Wales that watered Northern and Midland cities.’

‘I’m surprised you know. Causing political tension. Militant factions. Just as with the Water Train.’

I have the weird conviction Ms Williams is going to swallow Colin, flick out her tongue like a chameleon, and gulp him down in one.

‘There are always people who will look to destabilise society,’ she says. (She should have said derail.) ‘To create division.’

‘When they’re pushed to,’ Colin says, as if he’s proud of them.

‘Often because it serves them.’ Ms Williams seems unflapped. ‘Unfortunately, people will need to be displaced again. But in the case of hillside communities we are rebuilding new settlements. For them to relocate to. Most of them within short distances of their existing homes.’

‘Shanty towns! Out of rusty metal boxes.’ Colin must be hard to live with.

‘The re-use of containers from the decommissioned shipping yards provides a cost-effective and flexible solution with low eco-impact.’

‘But you’re still displacing families that have lived in a place for generations. Just as with the Ice Dock.’

‘Yes. But this is unavoidable. We live in a society. It isn’t always possible to take into account every individual. Policy always aims to arrive at a solution which helps the greatest number.’

Here it comes, from Colin . . .

‘By definition, then, the cities.’

. . . Setting me up perfectly.

‘But this is a key aspect,’ I interject, ‘of this Ice Dock project. It will serve the city from within the city. This won’t mean a community of farmers having their way of life destroyed so a distant town can have water. The people affected are from within the community that will benefit. It’s time for the city to take responsibility for itself.’

My silver bullet fired I look at the display cases around the room. A beautiful desiccated shoe, the archaeological finds uncovered during the build; the mural of the Dock site through the ages: the tower blocks flattened; Victorian causeways, a medieval bustle; a Saxon settlement upon the fen. The stadium suddenly disappeared, as if it’s lifted into space. They all look somehow interchangeable, these times, and humanised. Then there is the big white hole.

Ms Williams speaks passionately, is animated. She looks like a puppet, except she has no strings. Just the muscle memory that’s got her where she is.

We see another glorious digigram. A canopy of prisms focus sunlight on the ice. And Susan brings in glasses of cool ice water.

‘We want it to be cheap, and available to all,’ says Alan. ‘And municipal subsidies will help. The Mayor and most people in the city are fully behind the Dock.’

We break up the formal session.