The now-unclassified southern end of the former A778
The A778 was a short A-road that existed briefly at Monkton, to the north of Prestwick Airport in Ayrshire.
Following the construction of the A77 Prestwick and Ayr bypass, the A78 was diverted at its southern end to meet it. The short section of bypassed road into Monkton became the A778. It started on the A79 (former A77) in Monkton and headed north for about half a mile to reach the rerouted A78, which continued ahead. Following the construction of the new A79 perimeter road for Prestwick Airport (the route previously crossed the runway at-grade and so a diversion was badly needed), the A79 was also diverted away from Monkton, thus taking away the raison d'être for the A778. The road was therefore declassified entirely.
The A778 number appeared in the AA Book of the Road 1974's itineraries, although the route had already ceased to exist by then.
In 1958, the route is still part of the A78
The A778 is shown on the OS One Inch map from 1964