A Guide to the Longest Roads and Motorways in the UK

The UK has something of a love-hate relationship with its roads. On one hand, we dread their packed lanes, jams and tailbacks, especially on commutes to and from work. But on the other, we have some seriously beautiful routes that bikers and driving enthusiasts can’t get enough of.

Sure, there may be the occasional hold-up and not everyone is a fan of our national speed limits. But when all is said and done, we’re lucky to have such a safe, efficient and reliable road infrastructure.

To celebrate Britain’s great roads, we’re taking a look at some of the most impressive stretches of tarmac connecting towns and cities around the country. Here’s our guide to the longest roads and motorways in the UK.

What Are the UK’s Longest Motorways?

British motorways have been around for over 60 years, with the first being the Preston bypass, which opened in December 1958. Since then, the network has expanded rapidly and now covers over 2,300 miles.

But which of Britain’s motorways are the longest? Let’s find out.

1. M6 – 236 Miles

The M6 isn’t just the UK’s longest motorway; it’s also one of the oldest. Spanning from the original Preston bypass, the carriageway now connects central England with the Scottish borders, running for 236 miles between Catthorpe, Leicestershire and Gretna Green.

And what a journey it is! From the Midlands, the M6 takes you north, passing between the great cities of Liverpool and Manchester and onwards into the heart of Lancashire. From there, it’s a straight shot to the Scottish border, with the spectacular scenery of the Cumbrian Lakes to keep you company on the way.

Best roads in Cumbria2. M1 – 200 Miles

While the M6 may pip it on length, the M1 is arguably the UK’s most important motorway. Used by millions every year, this is the primary trunk route between north and south, connecting Yorkshire with London over a 200-mile journey.

The M1 was built in 1959, though there were plans to start construction before the Second World War. The earliest version of the carriageway had no crash barriers, lighting, speed limits or hard shoulders – which sounds like a disaster waiting to happen today.

3. M4 – 192 Miles

While the M1 and M6 are the main north-south motorways in the UK, the M4 is one of our longest east-west routes. Starting in Chiswick, London, the road cuts a course through the Thames Valley before crossing into Wales, stopping close to Swansea on the border of picturesque Pembrokeshire.

In recent years, the area around the motorway has earned the title of the M4 Corridor, particularly the towns and cities close to London. Described as the “Silicon Valley” of England, it’s now considered a major high-technology hub. But there’s a catch: the M4 is among the most congested motorways in the country.

What Are the UK’s Longest ‘A’ Roads?

When we think of long, cross-country roads, motorways are the first thing that come to mind. But it may surprise you to learn that many of our longest routes are ‘A’ roads – and by a considerable margin.

‘A’ roads represent some of the UK’s oldest travel routes, with the tarmac of today laid on paths trod long before cars came along. But which of these historic ways is the longest?

Driving to Edinburgh1. A1 – 410 Miles

In much the same way that the M1 is Britain’s most important motorway, the A1 is easily the most recognisable and significant road route in the country. Covering some 410 miles, the carriageway starts in the centre of London before heading north, passing through the Midlands, Yorkshire and Northumbria. From there, it crosses the Scottish border, ending in the centre of Edinburgh.

Though designated an ‘A’ road in the 1920s, the route of the A1 has been in use since ancient times. The Romans, Anglo Saxons and Normans all contributed to its expansion, and today the carriageway is still famous for its ‘coaching inns’ – used by road-weary travellers hundreds of years ago.

2. A38 – 310 Miles

The A38 is, without doubt, one of the most important roads in western England. Cutting a course from Nottinghamshire to Cornwall, its 310-mile span remains one of the most well-used routes into South West England, as it has done since the Romans devised it 2,000 years ago.

Returning to the present, the A38 has earned the affectionate nickname as the “holiday route” due to it being one of the main roads into Somerset, Devon and Cornwall. And even though the M5 motorway now serves the region, many travellers prefer the A38 for its scenery and nostalgia.

3. A30 – 284 Miles

At 284 miles, the A30 is the third-longest ‘A’ road in Britain and connects central London with Cornwall’s iconic Land’s End. For centuries, the route was the fastest way to get from London to the southwest, but now, like many ‘A’ roads, it’s secondary to a modern motorway (in this case, the M3).

Longest roads in the UKThe golden age of the A30 took place between the 18th and 19th centuries when the road became a popular coaching route between London and the West Country. Wealthy Londoners would travel by coach to holiday in Cornwall, Devon, Dorset and Somerset, while the road’s proximity to Bristol (at the time one of England’s most prosperous ports) also made it a valuable trade route.

Five Incredible Facts About Britain’s Roads

Keen to discover more about our amazing road network? Here are five choice facts we love about Britain’s roads.

  1. Our widest motorway has 17 lanes of traffic

You read that right. The M61 in Greater Manchester has a whopping 17 lanes, including eight hard shoulders. Sat nav at the ready for this one – you don’t want to get the wrong lane.

  1. The UK’s shortest motorway is under half a mile long

While the M6 is the longest motorway in Britain, the A635(M) is the shortest. At 300 metres, it’s about the same length as three football pitches. You’ll find it in central Manchester, as part of the Mancunian Way.

  1. The M62 is the highest motorway in the UK

That’s right, the M62 Summit is the highest portion of motorway in Britain, rising to 1,222 feet above sea level. You’ll see it marked by the side of the carriageway in the middle of the Peak District’s Saddleworth Moor.

  1. The M25 is the UK’s longest ring road

Encircling Greater London, the M25 is Britain’s longest ring road by a considerable margin, covering some 118 miles. Indeed, it used to be the longest in the world, until the construction of the Berlin Ringbahn, a 121-mile route around the German capital.

  1. The UK road network totals 247,100 miles of paved roads

Amazing, right? Almost a quarter of a million miles of road crisscrosses the UK, including 2,300 miles of motorway, 29,500 miles of ‘A’ roads, 18,800 miles of ‘B’ roads and 196,300 miles of ‘C’ and ‘U’ roads.

Have you enjoyed our guide to the longest roads and motorways in the UK? Head to the Redex blog for more motoring news and features. Or if you’d like to find out how to improve the life of your car’s engine with Redex fuel additives, visit the homepage.

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