Road: London Oxford Airport Motorway
Location: Longwick, Princes Risborough, Buckinghamshire
Date planned: 2012-2014
Grid reference: SP770065 (SABRE Maps)
Longwick services was a surprising consequence of the proposal to expand London Oxford Airport. In their supporting documentation, the airport included proposals for a new motorway linking the A34 to the M1, and those plans included an interchange with the A4129 near Longwick. This had land zoned for a service area in the north-western corner, accessed from one of two roundabouts.
Since the 1990s, motorway services haven't been included as part of the plans for new motorways, as they are developed privately. However in this instance, as the motorway is a private proposal, the developer can include any services they have in mind too.
The airport expansion plans are unlikely to ever get as far as requiring a new motorway, so the idea of it having a service area is almost fanciful.