M25 motorway "Inside the M25" and "outside/beyond the M25" are colloquial, looser alternatives to "Greater London" sometimes used in haulage. The Communications Act 2003 explicitly uses the M25 as the boundary in requiring a proportion of television programmes to be made outside the London area. Two motorway service areas are on the M25, and two others are directly accessible from it. Those on the M25 are Clacket Lane between junctions 5 and 6 (in the south-east) and Cobham between junctions 9 and 10 (in the south-west). Those directly accessible from it are South Mimms off junction 23 (to the north of London)
M25 motorway outside Heathrow Airport consistently records the highest number of daily traffic counts on the British strategic road network with a sample in 2017 measuring 211,059 counts (lower than the record peak measured in 2014 of 262,842 counts). This compares to 197,219 counts measured on the M1 motorway between junction 7 and 8 outside Hemel Hempstead in 2014, and 195,325 counts measured on the M60 motorway between junctions 12 and 13 in Western Manchester, also in 2014. The M25, plus the short non-motorway A282 which joins the two ends of the M25 across the River Thames using the Dartford Crossing, is