There have been various plans for a service station on the M25 between J27 and J28. This page aims to cover them all.
Hill Hall, which is referenced in almost all of them, is an Elizabethan mansion which has recently been restored by English Heritage.
There is already an emergency exit where the M25 crosses Mount Road.
References to the original planned services are few and far between. Firstly, it's important to note that what is now roughly the northern and eastern parts of the M25 was originally going to be called the M16, and be completely separate from the rest of the road.
Little attention was given to services on the M16, as there were so many question marks over its route. When Essex County Council and Granada suggested possible services near Thurrock, the Department for Transport said they preferred their proposed Hill Hall services, despite noting that it was likely to encounter environmental objections.
After the M16 and M25 were eventually merged into one motorway, the easy option was to build services at South Mimms and Thurrock, leaving Hill Hall out of the picture. By the time the new road was finished, the private sector were allowed to propose new sites for services, so it was decided to leave the area alone unless a company offered to take it on.
In 1994, Chantry Property wanted to provide a motorway service area on the site, to convert Hill Hall to provide hotel and leisure facilities, and to convert Colemans Farm into a golf course and club house.
These proposals were specifically written-off as being inappropriate, although a Department for Transport press release claimed services would be opening at Theydon Mount (here).
Another plan from Chantry Property, this time made in partnership with the Argent Group, described itself as both a "motorway service area" and a "golf course, club house and restoration of the hall", all utilising the land at Colemans Farm. This appears to have been taken to a public inquiry.
In 1994 Dashswivel proposed a full motorway service area, on land "adjacent to" Hill Hall.
They appeared to argue that Hilton Park proves you can use a stately home as a backdrop for a service area, although it was pointed out Hilton Park is heavily screened from its namesake manor.
Two services were also planned at J26 and were debated at the same time, although they are listed on the Waltham Abbey page.
The inspectorate ruled that all these services were in special landscape areas and nature conservation zones. While Epping District were keen to see Hill Hall restored, they didn't believe any of these plans supported that.
The sites at Hill Hall would have been a problem with motorway widening and the exit for the M11 to the north-west.