The M25, Britain’s busiest motorway and the road to hell or at least from hell for many London drivers, is about to turn 30 years old.

Some say the 117-mile London orbital road has changed lives for the better by boosting economic growth and creating better links between surrounding areas and the rest of the country.

But others claim all it has done is attract more and more traffic - earning it a reputation as the nation's largest car park.

The M25 was designed to carry up to 100,000 vehicles each day, but nearly double that use the motorway today.

The first part of the M25 opened in September 1975, with the final 13-mile section opened by then prime minister Margaret Thatcher on October 29, 1986.

There was talk of the M25 being only two lanes wide at one stage but it opened with three lanes in each direction, with various widening schemes introduced as the years went on.

Drivers could face major delays over the coming years during work to expand Heathrow Airport.

The M25 will be required to run underneath the third runway - either by digging a tunnel or constructing the runway on a slope over the road.

A Highways England report published by the Department for Transport warned of a "substantial risk of excessive customer frustration" during what could be a "prolonged period of disruption" for drivers.

HE regional director Simon Jones said the M25 plays a "vital role" in getting people to their destinations.

He went on: "Thirty years since its opening in 1986, the M25 continues to boost economic growth as well as providing the surrounding communities with vastly improved links to the rest of the country.”

AA spokesman Jack Cousens said: "The M25 is an important strategic road, but it is subject of much derision from the public.

"We wish the M25 a happy anniversary, but hope that within the next 30 years answers are found to the eternal problems of congestion."

9 facts about the M25

  • At 117 miles it is the second longest city bypass in Europe, behind the 122-mile Berliner Ring in Germany.
  • The section to the west of London around Heathrow Airport is one of the busiest parts of road in Europe.
  • The M25 has 33 junctions and 234 bridges, including the Queen Elizabeth II Bridge at the Dartford Crossing.
  • It was the inspiration for Chris Rea's 1989 hit song The Road To Hell.
  • The route was subject to no fewer than 39 public inquiries lasting a total of more than 700 sitting days.
  • The inquiries led to the doubling in length of the tunnel at Epping Forest in Essex and extensive cuttings near Swanley and Sevenoaks in Kent to shield an area of outstanding natural beauty.
  • In total, two million tonnes of concrete and 3.5 million tonnes of asphalt were used during construction.
  • More than 2.1 million trees and shrubs were also planted.
  • The full motorway construction at the time cost £909 million over 11 years, or roughly £7.5 million per mile.