Tetsworth services would have been a service area on the M40 between J6 and J7. For a while it looked like Tetsworth would have been the plan that went ahead; most documents refer to services being pursued at "Barn Hill, Ardley and Tetsworth".
The services would have had looped sliproads to the east of the site, with the facilities themselves being to the west, very similar to Reading which was built at the same time.
There would have been 200 car parking spaces.
After planning permission was refused in 1991, attention started turning towards nearby Stokenchurch services. In fact Oxford, the services which were eventually built, wasn't taken very seriously for a long time before it was given planning permission.