The M25 was 40 years old on 29 October. Its queues helped inspire Chris Rea’s 1989 hit The Road to Hell, while it’s also been called the UK’s biggest car park. Those nicknames have proven rather harder to shift than the traffic, yet the M25 has also inspired sightseeing trips and acquired a following for some of its graffiti; there’s even a cricket ground above it.

New research to mark the big birthday shows just how much businesses still depend on London’s orbital motorway, yet a quarter of local van drivers have declined jobs because journeys on the M25 are just too unpredictable.

Margaret Thatcher opened the final section of London’s orbital motorway on 29 October 1986, completing a route intended to take traffic away from London and surrounding towns. The idea of an outer ring road had been discussed as far back as 1905, with the first stretch, between South Mimms and Potters Bar, opening in 1975 and the final link between London Colney and South Mimms following 11 years later.

Even at the opening ceremony, there were complaints that it wasn’t big enough. Thatcher was having none of it, criticising “those who carp and criticise when they ought to be congratulating Britain on a magnificent achievement”. However, widening a section was already on the government’s to-do list.

The 117-mile motorway doesn’t quite complete the circle, either: the Dartford Crossing is officially the A282. And its first service area arrived after the completed road, with South Mimms opening in 1987 and Thatcher returning for the official ceremony that June.

Building it also involved planting some two million trees to help it blend into the countryside. Near Epping, a cricket ground was reinstated above the Bell Common Tunnel, giving the M25 an unusually sporting roof.

Perhaps the biggest surprise is that people have paid to spend their leisure time on it. In 2012, a four-hour sightseeing coach tour around the M25 cost £15 a head and sold out, prompting extra dates. Heathrow’s Terminal 5 and a shopping centre were among the attractions. For once, four hours on the M25 was part of the plan.

Even its graffiti became a landmark. The “Give Peas a Chance” message on the Chalfont Viaduct, between junctions 16 and 17, had a Facebook following of more than 8,000 by 2018. When it was painted over that September, a petition called for its restoration and protection.

The M25 has other cultural connections, too. Dance duo Orbital took their name from the road and the rave scene around it. In Terry Pratchett and Neil Gaiman’s Good Omens, meanwhile, the motorway is treated as evidence of demonic interference. It’s quite a reputation for something that was supposed to make getting around London a little less stressful.

There’s a much more serious side to its history, too. On 11 December 1984, before the full route had opened, nine people were killed in a 26-vehicle pile-up in dense fog. The police investigation identified excessive speed by some drivers for the conditions and Ministers subsequently announced trials of fog detectors on the motorway.

Its safety record today needs a little care in the telling. Analysis of Department for Transport data for 2021 to 2025 shows the M25 recorded about 7.5 injury collisions per 100 million miles travelled by vehicles, compared with 4.8 on the M1. However, its rate of fatal collisions was lower. Motorways generally also compare favourably with other roads: in 2025, they carried 21 per cent of Great Britain’s traffic but accounted for 6 per cent of road deaths.

For businesses, those queues can still be costly. A survey commissioned by vehicle data company Geotab, involving 1,000 regular M25 van drivers from the South East, found 84 per cent said their businesses couldn’t operate as effectively without it. Some 79 per cent described it as frustrating, while a quarter had declined jobs because journeys could be too unpredictable.

Geotab’s separate analysis of connected vehicles, found the M25’s eight most congested stretches were all between junctions 10 and 20. Across 12 sample weeks between September 2025 and August 2026, the clockwise journey from Heathrow towards the M4 averaged 9.2 minutes at 4pm, compared with three minutes at 7pm.

Geotab vice-president Aaron Jarvis said, “The M25 is easy to complain about, but the research shows how much businesses across the South East depend on it. For many operators, there simply isn't a practical alternative.”

Asked what would help keep traffic moving on the M25, drivers favoured a range of improvements, including quicker incident clearance, better coordination of roadworks and better traffic information.

Forty years on, that’s a fairly practical birthday wish list. The road to hell still has an essential job to do; its regulars would simply like a better chance of arriving when they said they would.