Described as the ‘road to nowhere’, the M25 may have many critics – but three decades after it was opened it’s hard to imagine the landscape of the south of England without the 117-mile London bypass.

The orbital motorway was opened by Prime Minister Margaret Thatcher just three days after the financial sector’s 'Big Bang'. It was as much a monument to Thatcherism as the deregulation of the City of London, and she saw it as an opportunity to highlight British success.

[Quiz: How well do you know Britain's motorways?]

"It's a great engineering achievement,” she said at the opening ceremony. "Fly the flag for Britain. You've got the message?"

Margaret Thatcher cuts the ribbon to declare the final section of the M25 open.

The motorway was the culmination of a plan first devised in the early 20th century. The idea of an orbital road around London was then re-examined in Sir Edwin Lutyens' Highway Development Survey of 1937.

Finally, in the 1970s, the road began to take shape. It took more than 11 years to build, cost £1 billion and used more than two million tonnes of concrete and 3.5 million tonnes of asphalt. It is a monster of a road – but early critics pointed out its destinations weren’t exactly high on anyone’s holiday list: Clacket Lane, South Mimms, the Dartford Tunnel, Staines. The point, however, was to ease the congestion through London, giving drivers a chance to go from north to south or east to west, without having to go anywhere near the capital’s busy streets.

It also had a huge effect on people’s relationship to the capital and the countryside around it and has become a verbal reference when referring to London and the rest of the country – the phrases "inside the M25" and "outside the M25" are now common parlance.

The M25 also increased house prices for many. "We know from our research that house prices generally have gone up about 300% since the M25 opened in 1986," Anthony Wardell from Knight Frank estate agents said in 2011. On the western side of London, house prices had gone up nearer to 400%, he added.

The need to widen the M25 from its original three lanes to as many as six has resulted in regular roadworks.

But it didn’t take long for the motorway to reach capacity, and it saw some huge traffic jams which led to the M25 being dubbed 'Britain's biggest car park'. Chris Rea’s song The Road to Hell was written explicitly about being snagged up in one of the many jams which affected the road. Author Terry Pratchett even said it was proof of “the hand of Satan in man”.

Widening quickly followed from the original three lanes to four-, five- and in some places six-lane carriageways, but the inevitable roadworks didn’t help dispel the image of the M25 as a permanently snarled-up queue of cars.

Despite all this it is still with us, carrying holiday-makers to London’s two main airports, families to Legoland and Windsor Castle, and tired commuters home – eventually.