Is there a 10% + 2 leeway on speed cameras?
Sort of. Most police forces in England & Wales follow NPCC guidance and normally start enforcing once you reach the limit plus 10% plus 2 mph. But it's guidance, not law — and it doesn't mean speeds below it are “allowed”.
When enforcement usually starts, by limit
| Limit | Usually no action | Enforcement from | Course range |
|---|---|---|---|
| 20 mph | 21–23 mph | 24 mph | 24–31 mph |
| 30 mph | 31–34 mph | 35 mph | 35–42 mph |
| 40 mph | 41–45 mph | 46 mph | 46–53 mph |
| 50 mph | 51–56 mph | 57 mph | 57–64 mph |
| 60 mph | 61–67 mph | 68 mph | 68–75 mph |
| 70 mph | 71–78 mph | 79 mph | 79–86 mph |
The threshold is the limit plus 10% (rounded down) plus 2 mph. Exact practice varies by force.
Why the margin exists
Speedometers are allowed to over-read but never under-read, and enforcement equipment has its own tolerances. The 10% + 2 margin gives drivers the benefit of the doubt and lets forces concentrate on clearer offences.
Why you shouldn't rely on it
- It isn't law. Any speed over the posted limit is an offence, and officers can act on it.
- Forces can set tighter thresholds — for example near schools or on roads with a poor safety record.
- It's based on the recorded speed, not what your speedometer showed.
Just over the threshold?
If you were caught at or a little above the threshold, the most common outcome for a first offence in 3 years is a speed awareness course — no points and no fine. Above the course range it's usually a £100 fixed penalty and 3 points. See exact outcomes for 36 in a 30, 74 in a 70 or 82 in a 70.
Common questions
Is there a 10% leeway on speed cameras?
Most UK forces follow National Police Chiefs' Council guidance and start enforcing at the limit plus 10% plus 2 mph — 35 mph in a 30, 79 mph in a 70. It is guidance, not law: any speed over the limit is an offence and some forces or cameras are set tighter.
Will I get points for doing 36 in a 30?
Usually not, if it is your first offence in 3 years. 36 in a 30 is inside the typical speed awareness course range (35–42 mph), so most people are offered a course instead of points. If you're not offered one, it's normally a £100 fine and 3 points.
Will I get a fine for 74 in a 70?
Unlikely. 74 in a 70 is below the 79 mph point at which most forces start enforcing, so action is rare — but it is still technically an offence and the decision is at the police's discretion.
Enter your exact speed to see the likely outcome.
Open the speeding fine calculator →