The careful speed was maintained until they passed, on their right, a ramshackle manoir so run-down it was shorn of windows, fronted by a clutter of delapidated farm buildings with a couple of canvas-topped lorries parked outside, which seemed to be a workshop for farm equipment, judging by the amount of rusting metal and tractor attachments scattered about.

Cal sounded a tattoo on his horn, before swinging on to a narrow bridge with a low stone parapet that led to the north side of the canal, followed by a glance upstream to check the barge containing his cargo was still moored where he had last seen it. Now hidden by the line of trees that enclosed the canal on both sides he increased his speed, jamming his foot to the floor; if it gave him a pleasing sensation of haste, it was, he knew, useless by comparison to that of the car behind.

The road ahead split again and he screeched round the right-hand bend, gunning through the gears to another junction and swinging left onto an equally narrow, long and straight road that led north away from the canal — not that he expected to fool anyone and get away.

He had only one aim: to see if it was indeed a tail, or if he was being overcautious; that was answered within minutes when those big twin headlights abreast the low-slung black body appeared once more in the rear-view mirror. Cal immediately killed his speed, noting that the tail slowed as well. They were definitely being followed, but by whom?

What he had said to Peter had to be true: it was unlikely to be official, and not just for the value of a car that cost as much as a Rolls-Royce. If it was the French equivalent of MI5, seeking to enforce their national embargo on weapons destined for Spain, they would have been much more professional and thus harder to spot.