From there, they were loaded on to a purpose-built narrow gauge railway which carried them through an airlock in sealed wagons right up to the doors of the huts, only unloaded once they were inside in the strictly-controlled air-conditioned space.
However, Ms Bosman said it did not always run that smoothly.
“Van Dyck’s Equestrian Portrait of Charles I is a monster, at 12ft by 9.5ft, and in its case, loaded on the back of the truck, it was considerably taller,” she said.
“On the approach to the quarry there is a tight S-bend, just where the road passes under the arch of a railway bridge.
“I liken it to trying to get a sofa around a corner on the stairs; there was enough height, but only if you could hit precisely the right angle.
“In the end they had to dig up the road surface to lower it by a few inches, and to this day you can see how the kerb in that section is noticeably higher than on the rest of the road; it’s a measure of just how important the evacuation was.”
