The M40 runs from London to Birmingham via Oxford, but it's really two separate projects from two different eras. In the 1960s, work started building a motorway from London to Oxford, bypassing the congested A40, and this part was complete by 1974. It was mainly dual two-lane and it returned traffic to the A40 Wheatley Bypass at the Oxford end for the final approach to the dreaming spires.
In the late 1980s and early 1990s, the M1 and M6 route from London to Birmingham was suffering chronic congestion, and the solution came in the rebirth of the M40. A long new section was built, branching off the original motorway just short of its Oxford terminus and running to the M42 on the outskirts of Birmingham. This had been planned for many years - indeed, even in the early 1970s Oxford was described as a "temporary motorway terminus" - but by the time it came along, with the majority of this new route opening in a single jump in 1991, it was a quite different proposition to the M40 built in the sixties. The new motorway is dual three-lane throughout, with very few junctions and very generous curves and gradients.
The existing motorway was also refurbished to match it, with a substantial length widened to four lanes at the London end, to help provide capacity for Birmingham traffic on the existing road to Oxford.
The new section suffered a number of controversies. From Wheatley to Bicester, the line of the motorway was fiercely debated, and consideration was given to creating a substantial detour by upgrading the existing A40 and A34 between those points. The Department of Transport decided to ignore the outcome of its public inquiry and routed the motorway across Otmoor, an area of wetland that was of particular value to wildlife. In response, Friends of the Earth bought a plot of land on Otmoor, which they named Alice's Meadow, and sold it off piece by piece to 3,500 people. In order to build the M40 on its preferred line, the DTp would then have had to go through the whole Compulsory Purchase and appeals procedure 3,500 times. The protest was successful and the M40 now passes around the edge of Otmoor instead.
When it first opened, there were no services on the M40. Not only did this mean that the reasonably long drive from London to Birmingham could be done without passing a fuel station or toilet, the motorway's position in the national network - and the lack of services on either the south side of the M25 or the M20 in 1991 - also meant that it was actually possible to drive from Folkestone to Birmingham without passing any services. HGV traffic on the new motorway was minimal because lorry drivers had nowhere to stop to take their mandatory breaks. Initially relief was provided by a parking area and a temporary installation of portable toilets at the site that would later become Cherwell Valley services. The M40 now has full motorway services at Beaconsfield, Warwick and Oxford too.