Google says the smartglasses are still in beta – prototype – form, despite being openly on sale, and that it wants early adopters to buy and use them and report back problems and suggestions so it can shape the future of the product, which is expected to eventually cost about the same as the average smartphone.

But what is really important about Cragside is its interior; because here Armstrong the inventory and engineer let himself go. In 1868 he installed one of his own hydraulic engines, with which he powered his laundry equipment, a primitive sort of telephone, a passenger lift, a Turkish bath and even a rôtisserie.

He forfeited his last chance of an early release from jail by repeatedly attacking another inmate.

If we're done, I'll be on my way.