Hate it or only hate it a little bit, the world's largest circular car park the M25 is a motorway we all have to use at some stage.

The idea for a giant motorway surrounding London gathered momentum in the late 1960s, and by the late 1970s construction was underway.

Then Prime Minister Margaret Thatcher officially opened the M25 in 1986, although many of the sections were completed either before or after that year.

Some people say that in many ways the beleaguered road is a victim of its own success.

Other people claim that there must be some fundamental design flaws to explain why it doesn't appear to work very well.

The south west section, stretching from junction 16 the M40 to junction 7 the M23, is acknowledged as one of the busiest stretches of road anywhere in the country.

To celebrate this remarkable route we've put together a list of a few things only M25 drivers will know.

As ever, please add comments below on anything we've missed out.

1) Uh oh, the signs say 40mph

On some roads the overhead signs telling motorists to drive at 40mph mean that traffic will move at 40mph. On the M25 the 40mph signs mean traffic will soon be at a standstill for at least 20 minutes. In many ways they should develop a 0mph sign.

2) The longest part of any journey

This is Colin Clark in Glasgow, but he could easily be on the M25, given his expression

Every driver knows that if you're undertaking a 150 mile journey to another part of the UK, the 15 miles you have to do on the M25 will take as long as the previous 135.

Try as you may to find a way to avoid the iconic ring road, it usually proves impossible.

3) Horrible smell


Anyone else noticed the horrible smell at junction 12 for the M3? It's most unpleasant. Even more so if you're stationary in your car, which is the usual state of affairs. Swinging down onto the M3 the smell becomes more pungent, and it is a relief when one motors away from the fetid aroma.

4) Admiring the planes

Ooh airplane

When you reach junctions 13, 14 and 15 you will often get the chance, if sitting in the customary traffic jam, to admire the planes coming out of Heathrow and the airport control tower.

Thoughts often turn to jetting off to a sunny place and lazing around on a white sandy beach. Then you realise you can't afford to go away.

5) Cobham services

Cobham services
Cobham services

Obviously Cobham Services is a great asset and has proved to be a popular addition to the south west section. But why can't it be on both sides of the motorway like normal major services?

It can be most tedious accessing the services if travelling on the anti-clockwise section.

6) Toilet break

The cubicle where Boo Sripichit was stuck for half an hour
I need a weeeee

If you don't happen to be near Cobham Services, and are more towards the junction 15 area, it can be a major problem if one requires a toilet break.

Attention can soon turn to if there's a possibility you could take a pee in your car. Is there an empty bottle that could do the job? Or another suitable receptacle? Traffic isn't moving and I need a peeeeee, aaarrgghh.

7) Long junction

It's a long 6.6 miles

Travelling from junction 8 Reigate to junction 9 Leatherhead, or the other way round, can take what seems like an eternity, yet in depth research reveals the route to only be 6.6 miles. So why does it feel at least three times longer than that?

Perhaps it's the undulating landscapes and abundance of green fields. Or the occasionally iffy road surface in some sections. Whatever the reason, the phenomenon is one of life's great mysteries.

8) Why traffic, why??

Boo traffic

When one is sat, bumper to bumper, idling away the hours in M25 traffic, it is common to think of the cause of such a delay. You listen intently to the radio for traffic updates - although M25 congestion barely gets a mention nowadays as it's so commonplace - but there don't appear to be any major incidents.

Then, when one gradually makes their way through the traffic and out the other side, there's nothing there. Not a single sign or reason for the hold-up. Why were we all queuing? There must be a cause somewhere. It's a circular road, surely all the cars can just go round and round and round? Another unsolved mystery caused by the great road.

9) Cows

How now brown cow

Many parts of the south west section are blessed with beautiful rolling green fields. In said fields can often be spotted cows and other animals, how do they all stand the noise and commotion?

Cows in particular look unflustered by all the action unfolding before them on "the big concrete bit that we're not allowed on", as they probably call the M25.

Admittedly cows can look unbothered by many things, but I would've thought they'd make an exception for the M25.

10) One mile to go

A brake (albeit for a Tornado)

The "one mile to go" or half-a-mile to go" and especially the unusual "third-of-a-mile to go" signs to warn people to prepare to get off at junctions can prove problematic.

They can install uncommon amounts of fear in even the most levelheaded motorists. Pity any motorist following one of these brake-happy junction-worriers.

11) Lorries

Oh dear

There have been unfounded and totally unbacked up theories that a major cause of most of the traffic on the M25 is lorries overtaking other lorries.

Or other heavy goods vehicles overtaking other heavy goods vehicles.

At this stage it's just a theory but further research will take place to try and get to the bottom of this issue once and for all.

Download now from the App Store or Google Play for Android.