|Distance:||10 miles (16.1 km)|
|Meets:||M20, M25, A20|
|Former Number(s):||M25, M20|
|Route outline (key)|
It is unusual in that its only unique junction, 2a, is numbered according to another motorway's numbering scheme, in this case M20. This is due to it originally being part of the M20 (as junction 3), with the planned line of the M20 taking a slightly more southerly route than today's, when the M20 was extended westwards towards London. However, most of the original M20 part of the M26 has been demolished when the fork junction with the more northerly option of the M20 route was built.
Main Article: Chevening Interchange
The Chevening Interchange is a restricted access freeflow interchange between the M25, M26 and A21 northwest of Sevenoaks. It is notorious for requiring a TOTSO for M25 traffic, and having no turn offs for the M26 westbound and A21 northbound.