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8 Surprising UK Driving Laws You Might Be Breaking

June, 4 2025 | James Russell

From flashing lights to roundabout rules, here are the quirks, myths, and truths of UK driving.

 

8 Surprising UK Driving Laws You Might Be Breaking

Whether you passed your driving test last week or last century, chances are there are a few Highway Code rules you’ve forgotten, or maybe you never knew them at all. And while some of them seem like ancient trivia (when was the last time you saw a horse-drawn cart on the A1?) Others could land you with points, fines, and embarrassment if you’re pulled over.

So, here’s our roundup of 8 surprising Highway Code rules and UK driving laws you probably didn’t even know that you were breaking.

1. Flashing Your Headlights Isn’t A Thank You

We’ve all done it. A quick, friendly flash of the headlights to say thanks when someone lets you out at a junction, or gives way on a tight road. But technically, just like the car horn, that flash is only supposed to mean one thing: “I’m here”. Not thank you or “go ahead”, and definitely no passive-aggressive “hurry up”.

This is important because if flashing your headlights causes an accident because the other driver misunderstood your intention, you could be partially liable. 

2. Roundabout ‘Courtesy’ isn’t Always Correct

Some drivers are taught to give way to the right at mini roundabouts, regardless of who’s already on it. According to the Highway Code, however, this isn’t the way to do it because if you’re already on the roundabout, you have priority. 

Aerial photo of black and white roundabout in Bedford

Nevertheless, we always see drivers slam on the brakes or wave others through like it’s the polite thing to do. Don’t get us wrong, being courteous is great, but being confident (and correct) is safer.

3. Middle Lane Hogging Isn’t Just Annoying – It’s Illegal

There’s nothing quite as annoying as somebody sitting in the middle lane of a motorway doing 65 miles per hour. It not only irks every other driver on the road, but it causes unnecessary congestion. 

We all know this, but what you might not know is that it’s also punishable with a £100 fine and three points on your license. Why? Because the middle lane is for overtaking, so, once you’ve passed the slower traffic, get back into the left-hand lane. 

The DVSA even ran a campaign titled “Don’t Be a Hog”, but many motorists seemingly missed it, as we regularly see middle lane “hoggers” on our morning commute.

4. You Can Cross a Solid White Line... Sometimes

Normally, a solid white line in the middle of the road means “no overtaking”, but there are exceptions.

According to Rule 129 of the Highway Code, you can cross a solid white line to pass a stationary vehicle, cyclist, horse, or road maintenance vehicle, for example. The rule of thumb is that they have to be travelling at 10mph or less.

So yes, you can overtake that tractor crawling at a snail’s pace, just don’t use it as an excuse to go flying past everything in sight.

5. Number Plates Must be Clean

A dirty number plate can get you fined up to £1,000 if it’s unreadable. Even a light layer of grime that makes a character ambiguous (like a B that looks like an 8) can land you in trouble.

This is because Automatic Number Plate Recognition (ANPR) cameras can struggle to read plates if they’re too dirty. That’s a problem at petrol stations, car parks, and even toll booths. So, the next time you’re wiping down your windscreen or giving your car a jetwash, give your number plates some love too.

6. Horns Have a Curfew

You can’t use your horn on a restricted road between 11.30pm and 7am, unless it’s a genuine emergency. So, if someone cuts you up at midnight and you lay on the horn out of frustration, you're technically in the wrong.

It’s also worth knowing that using your horn aggressively, like beeping at someone who hasn’t pulled away the second the light turns green, can count as anti-social driving.

7. Splashing Pedestrians Isn’t Just Rude

If you drive through a puddle and drench someone on the pavement, it’s not just embarrassing. It can also count as driving without reasonable consideration for other road users. There are even cases where drivers have been fined hundreds of pounds for deliberately (or carelessly) soaking pedestrians. 

Car driving through puddle black and white

The moral of the story is to slow down and steer around.

8. Your Number Plate Must Have the Right Font, Colour, and Spacing

No fancy italics. No extra bolts to turn a “3” into an “E”. And absolutely no neon. UK number plates must follow strict rules for font, spacing, and layout, and if yours doesn’t, you can fail your MOT, get fined, or have your car impounded.

BSAU number plate rules explained in image

At National Numbers, we sell personalised plates that are 100% road-legal, and we’ll never let you buy one that isn’t.

Stay Sharp Behind the Wheel

The Highway Code is one of those things most drivers learn once and then never read again, but brushing up on it can make you a safer, smarter, and more confident driver.

And if you’ve got a number plate you’re proud of, the last thing you want is to get caught out for something silly like a muddy plate or a horn beep at midnight.

So stay safe. Stay informed.

And if you're ready for a plate that stands out (legally, of course),browse our vast stock of private registrations online or call 01642 363738 for more information.


 

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