M25 marks 40 years since Thatcher opened its final stretch

Mixed · 2The M25 turned 40 on 29 October 2026, four decades after Margaret Thatcher opened its final stretch on 29 October 1986. 1 2 Mixed · 2The 117-mile route was built in stages: the first section opened in 1975 and the last link, between London Colney and South Mimms, followed 11 years later. 1 2 Left · 1The Mirror reports it cost almost £1 billion and used more than two million tonnes of concrete; it was designed for around 100,000 vehicles a day, a figure usage soon exceeded. 1

Centre · 1At the opening, Thatcher called it a "magnificent achievement" and dismissed critics; the Standard says there were already complaints that it wasn't big enough, and widening a section was already on the government's list. 2 Left · 1According to accounts from the time cited by the Mirror, a breakdown was reported on an open section minutes after the ribbon was cut at around 11.15am, and queues had formed by evening. 1 Centre · 1The Standard notes the road does not quite complete the circle, as the Dartford Crossing is officially the A282, and that its first service area, South Mimms, opened in 1987. It adds that about two million trees were planted and a cricket ground was reinstated above the Bell Common Tunnel near Epping. 2

Mixed · 2Both outlets link the motorway to Chris Rea's 1989 hit The Road to Hell, said to be inspired by being stuck in its traffic, and to the nickname "Britain's biggest car park"; both also tie it to rave culture. 1 2 Left · 1The Mirror recounts that 84-year-old Dorothy Taylor of Ipswich circled the motorway repeatedly over three days after a wrong turn, and that Just Stop Oil activists climbed gantries in November 2022 despite a High Court injunction obtained by National Highways; five organisers were later jailed. 1 Centre · 1The Standard adds that a 2012 four-hour sightseeing coach tour cost £15 and sold out, and that the "Give Peas a Chance" graffiti on the Chalfont Viaduct drew an 8,000-plus Facebook following before it was painted over in September 2018. 2

Centre · 1The Standard also recalls that nine people died in a 26-vehicle pile-up in fog on 11 December 1984, before the full route opened. 2 Centre · 1Its analysis of Department for Transport data for 2021–2025 shows about 7.5 injury collisions per 100 million vehicle miles on the M25 against 4.8 on the M1, though the M25's fatal collision rate was lower. 2 Centre · 1A survey commissioned by vehicle data company Geotab of 1,000 South East van drivers found 84% said their businesses could not operate as effectively without the M25, 79% called it frustrating, and a quarter had declined jobs because journeys were too unpredictable. 2

Centre · 1Geotab's connected-vehicle analysis found the eight most congested stretches were all between junctions 10 and 20; the clockwise Heathrow-to-M4 journey averaged 9.2 minutes at 4pm against three minutes at 7pm. Drivers wanted quicker incident clearance, better roadworks coordination and better traffic information. 2