UK dash cam law, sourced
Are dash cams legal in the UK?
Dash cams are legal in the UK, and the rule that actually governs where you can mount one has nothing to do with millimetres. Regulation 30 of the Construction and Use Regulations 1986 requires that the driver has a full view of the road and traffic ahead. It does not set a size, a distance from the mirror, or a number of any kind.
Every motor vehicle shall be so designed and constructed that the driver thereof while controlling the vehicle can at all times have a full view of the road and traffic ahead of the motor vehicle.
This is the actual law on windscreen obstruction. It contains no measurement of any kind.
That single sentence is the whole of the law on where a dash cam can sit. Everything else you have read, a 40mm rule, a 10mm rule, a Highway Code size limit, is a number borrowed from somewhere else and applied to dash cams by websites, not by government.
This is not legal advice. This page reports what the sources below say. We are not solicitors, and we do not fit or test dash cams. If you need advice on your own situation, speak to a solicitor.
The "40mm rule" does not exist
Type "40mm dash cam rule" into a search engine and you get a confident number back. Follow that number to its source and it changes meaning at every step.
The actual law
Regulation 30, shown above, is the real rule. It contains no measurement at all.
The MOT manual
The MOT inspection manual sets 10mm and 40mm thresholds, but they are failure sizes for chips and cracks in the glass at your annual MOT, across two zones (zone A is 290mm wide, centred on the steering wheel). The manual does not mention a dash cam anywhere.
damage in windscreen zone A more than 10mm in diameter ... damage in the remainder of the windscreen’s swept area more than 40mm in diameter
These are failure thresholds for chips and cracks in the glass at the annual MOT. The manual does not mention dash cams anywhere. Zone A is 290mm wide, centred on the steering wheel.
The 2010 DVSA note
A DVSA and DfT note, published 1 May 2010, took the MOT's damage zones and applied them to objects: stickers, pennants and sat nav monitors, as a practical yardstick for windscreen obstruction. It says a non compliant item "could be construed to be in contravention of the legislation". It does not mention dash cams either.
Items placed in, or stuck to, the windscreen could be stickers, pennants, satellite navigation monitors or decorations.
This is the only document that applies the MOT zones to objects rather than damage. It was published in 2010 and does not mention dash cams once. It says non-compliant items "could be construed to be in contravention of the legislation".
Three documents, one number borrowed twice, and not one of them names a dash cam. Regulation 30 asks for a full view of the road and traffic ahead, and none of the sources we cite says that any particular mounting position satisfies it. The 40mm figure is a practical guide that people apply to dash cams by analogy. It was never written for one, and we are not in a position to tell you where your camera may lawfully go.
What the Highway Code actually says
windscreens and windows MUST be kept clean and free from obstructions to vision
Sites that cite this as a numbered Highway Code rule are wrong. Annexes are not numbered rules.
That wording sits in Annex 6, not in a numbered rule. It says windscreens and windows must be kept clean and free from obstructions to vision, and it cites Construction and Use Regulations 30 and 61 among its sources. Regulation 61 covers exhaust emissions, not windscreens: it backs a different bullet in the same list. A site that quotes this as "rule number so and so" is quoting something that does not carry a rule number.
Audio and privacy: nobody has settled this
Two questions come up alongside the legality of fitting a dash cam: does UK GDPR apply to it, and do you need to register with the ICO? The honest answer to both is that the position is unsettled, and we are not going to pretend otherwise.
personal data processed in the course of a purely personal or household activity, with no connection to a professional or commercial activity
The examples the ICO gives are "writing to friends and family or taking pictures for your own enjoyment". Dash cams, cars and public roads are not mentioned.
UK GDPR carries an exemption for "purely personal or household activity". The ICO's own examples are writing to friends and family, or taking pictures for your own enjoyment. Dash cams, cars and public roads do not appear.
Held that home CCTV capturing a public footpath cannot rely on the purely personal or household exemption. We cite this via secondary legal commentary and have not read the judgment text ourselves.
The Court of Justice of the European Union held, in a case about a home CCTV camera capturing a public footpath, that recording a public space can defeat that personal use exemption. We cite this by way of secondary legal commentary and have not read the judgment text ourselves.
If any of your work vehicles have a dashcam or CCTV camera, you’ll need to register and pay a data protection fee to the ICO
The ICO’s only dedicated dash cam guidance is written for businesses. It says nothing about a private individual’s dash cam. That silence is the finding.
The ICO's only dedicated dash cam guidance is written for businesses. It says nothing about a private driver's own car. That silence, not a stated rule, is the finding.
It is very difficult to reconcile the ICO’s position here with the case law as exemplified in Ryneš.
A data protection lawyer has said in public commentary that the two positions are hard to square. We are reporting that view, not adopting it.
Put plainly: nobody, not the ICO, not a court, not a solicitor writing about it, has produced a clear answer for a private driver's dash cam. Anyone telling you it is definitely fine, or definitely not, is going further than the sources go.
What the web says vs what the source says
Every myth we checked against a primary source while building this site. Some are corrected in full above, others get their own page because there was enough to say.
| What you'll read | What the source says | Sources |
|---|---|---|
| The law says a dash cam must not intrude more than 40mm into the swept area of the windscreen. | No law says this. Regulation 30 of the Construction and Use Regulations 1986, which is the actual rule, contains no measurement at all: it requires only a "full view of the road and traffic ahead". The 40mm and 10mm figures come from the MOT manual, where they are failure thresholds for chips and cracks in the glass. A 2010 DVSA guidance note applied those same zones to stickers, pennants and sat navs as a practical yardstick. None of those three documents mentions a dash cam. | The Road Vehicles (Construction and Use) Regulations 1986 , MOT inspection manual for private passenger and light commercial vehicles, section 3: visibility , DVSA and DfT, "View to the front and windscreen obscuration" |
| The Highway Code has a rule number covering dash cams. | The relevant text sits in Annex 6, which is not a numbered rule. It says windscreens "MUST be kept clean and free from obstructions to vision", and cites Construction and Use Regulations 30 and 61 among others. Regulation 61 is about exhaust emissions, not windscreens: it backs a different bullet in the same list. | The Highway Code, Annex 6: vehicle maintenance, safety and security , The Road Vehicles (Construction and Use) Regulations 1986 |
| Dash cams are exempt from UK GDPR because of the domestic purposes exemption. | The ICO defines that exemption narrowly, as a "purely personal or household activity", giving examples like taking pictures for your own enjoyment. It never mentions dash cams, cars, or filming a public road. The Court of Justice held in Ryneš that recording a public space defeats the exemption. The ICO’s only dash cam guidance is written for businesses and does not address the tension, and a named data protection lawyer has publicly said the two positions are hard to reconcile. The honest answer is that this is unsettled. | ICO, guide to the data protection exemptions , Ryneš v Úřad pro ochranu osobních údajů, Court of Justice of the European Union, C-212/13 , ICO, "Dashcams and UK GDPR: what small businesses need to know" , Jon Baines, data protection lawyer, "Dashcams and domestic purposes" |
| You have to register your dash cam with the ICO. | Only if you are a business. The ICO says work vehicles with a dashcam require registration and a data protection fee, which most small businesses pay at £52 a year. No such requirement is stated anywhere for a private driver. | ICO, "Dashcams and UK GDPR: what small businesses need to know" |
| You have 14 days to submit dash cam footage to the police. | Three different deadlines get conflated into one. Some forces ask for footage within 10 days. The 14 days is the statutory deadline for the police to serve a Notice of Intended Prosecution on the driver, under section 1 of the Road Traffic Offenders Act 1988. Six months is the limit for starting a prosecution for a summary offence. Full breakdown: the three deadlines | Devon & Cornwall Police, Operation Snap , Road Traffic Offenders Act 1988 |
| Insurers give you a discount for having a dash cam. | Some do. The ABI says "some insurers". Aviva says plainly on its own site that it does not, because a dash cam is portable and not permanently fitted. It does accept footage as evidence on a claim. Treat any blanket claim about discounts as marketing. | Association of British Insurers, dash cams , Aviva, dash cams knowledge centre |
| Your own dash cam footage cannot be used against you. | It can. Ask the Police, an official police information service, states that footage showing the person filming using a mobile phone, driving aggressively, or committing other traffic offences may result in them being prosecuted too. A practising solicitor says the same. Neither cites a specific reported case, so treat this as a documented risk rather than a proven precedent. Full breakdown: can it be used against you | Ask the Police (NPCC-backed public information service), Q942 , Neil Davies, senior partner, Caddick Davies Solicitors |
| Dash cam footage will get you done for speeding. | Named serving and former police officers describe the footage submission scheme as built for careless and dangerous driving, mobile phone use and close passes, not speed detection. We found no sourced example of anyone being prosecuted for speeding from footage they submitted themselves. Full breakdown: footage and speeding | Bennetts BikeSocial, legal FAQ, quoting Supt. Kevin Mulligan (Northamptonshire Police) and Dave Yorke (former Merseyside motorcycle police sergeant) , Ask the Police (NPCC-backed public information service), Q942 |
Questions
Is it legal to have a dash cam in the UK?
Yes. There is no law written specifically for dash cams. The rule that applies is regulation 30 of the Construction and Use Regulations 1986, which requires a full view of the road and traffic ahead and sets no measurement of any kind.
Is there a 40mm rule for dash cams?
No. No UK law sets a 40mm limit for dash cams. The 40mm and 10mm figures come from the MOT inspection manual, where they are failure thresholds for chips and cracks in a windscreen. A 2010 DVSA note applied the same zones to stickers, pennants and sat navs. Neither document mentions a dash cam.
Does the Highway Code give a dash cam size limit?
No. The relevant text sits in Annex 6, which is not a numbered rule, and it names no measurement. It says windscreens must be kept clean and free from obstructions to vision.
Do I need to register my dash cam with the ICO?
Only if you use it for work, such as a fleet vehicle. The ICO's dash cam guidance is written for businesses and does not mention private drivers.
Is recording audio on a dash cam legal in the UK?
Nobody has settled this. The ICO's personal use exemption is written narrowly and does not mention dash cams, a European court has held that filming a public space can defeat a similar exemption, and a data protection lawyer has said the two positions are hard to reconcile. We are not going to tell you it is settled when it is not.
Last reviewed 10 July 2026