The 117-mile-long orbital is one of the most important roads in the UK and one of the busiest.
Margaret Thatcher opened the final section on this day in 1986, making the M25 the longest ring road in Europe upon its opening.
But there’s a reason for its nickname with research by Opinion Matters finding 8 in 10 van drivers think it’s less reliable than 5 years ago.
Nearly a third of businesses say delays have led to customer complaints, while 1 in 4 have turned down jobs because of unpredictable journeys.
Geotab data shows the worst bottleneck is anticlockwise between Junctions 12 for Thorpe Interchange and 11 for Chertsey.
The busiest time for commercial traffic is 6 to 7am, but the worst delays are between 4 and 5pm.
