The cargo area was slick, no seats, and there was an added black Perspex partition to separate the cargo area and cab. There was a toybox, and toys strewn across the floor. A battery-operated small TV. A mattress and pillow and duvet with cartoon characters on the covers. Biscuit wrappers and crisp packets in a wire mesh bin, other snacks in a cardboard box. Sausage rolls. Bananas. Across the blacked-out back window was a large poster framed like a window and with a sea view. There were large stickers all over the walls and ceiling. Not quite the dank cellar Nick had imagined.

It was like a child’s bedroom.

‘They were constantly on the move? But where were they going?’

Miller explained. The Vito, which the female kidnappers must have swapped into at some point between the lock-up garage and the M1, had indeed gone south down the motorway, to the point twenty-five or so miles away on the A28 near Sutton – and Kirkby-in-Ashfield. Where the kidnappers made the 5 a.m. call to the house. East of the M1, because a slip road on the south run would poke east. They had simply pulled off and found a place to park.

The next call, to the hospital on a new mobile, had come a few hours later, but only eight miles south, in Nuthall – west of the M1. Not because the kidnappers had taken a slow journey on to the other side of the motorway, but because by then the van had travelled further south, turned around, and was heading north, which meant exiting to the left.

The final call from a fresh burner phone had originated again in Nuthall, but east of the M1 this time. Which was where you’d end up if you exited the motorway while travelling south. Not a zigzag. But:

‘A loop?’ Nick said. ‘They didn’t stop. They just drove up and down the M1 all night?’

DC Nabi had worked it out. He used the timeline of the phone calls to determine a loop between Sheffield and no further than Leicester, about seventy miles. Being on the motorway would allow them to travel anywhere they wanted quickly if they had to flee. They would know the police wouldn’t expect to find them on the move and police cars don’t often roam motorways. No chance of a random stop if they stuck to the speed limit. And the monotony of engine noise and vibration are said to simulate conditions in the womb, which is why young children so easily fall asleep in vehicles.

‘So he just watched and waited? And without telling you?’