A new investigation has revealed the different speed camera tolerances used by police forces across the UK.

Whilst it is a well known fact that speed cameras won’t flash you for driving just one mile over the limit, there are many urban myths as to what the actual threshold is, and there were wild rumours at the start of the year that motorway speed cameras had been set with no tolerance.

Following a Freedom of Information request to 45 different UK police forces, Auto Express has found the speed camera tolerances for forces in different parts of the country.

The majority of police forces stick to the guidelines issued by the Association of Chief Police Officers which suggests that cameras should only activate when a driver is breaking the speed limit by 10 per cent plus 2mph.

This ruling allows for a top speed of 79mph on motorways and 35mph in 30mph zones and in applies to both fixed and average speed cameras. There are a couple of police forces who allow for extra leniancy, with the Metropolitan Police and Lancashire Police using 1o per cent plus 3mph. There were some forces who refused to divulge the information claiming that it would encourage speeding.

Speed camera thresholds across the UK

Police force	Number of cameras	Camera activation threshold
Avon and Somerset	41	10% + 2mph
Bedfordshire	38	Would not reveal threshold
Cambridgeshire	32	Would not reveal threshold
Cheshire	15	10% + 2mph
Cleveland	4	10% + 2mph
Derbyshire	18	10% + 2mph
Devon and Cornwall	98	10% + 2mph
Durham	0 fixed	10% + 2mph
Essex	63	Don't use a standard threshold
Greater Manchester	235	Would not reveal threshold
Gwent	21	10% + 2mph
Hampshire	36	10% + 2mph
Hertfordshire	53	Would not reveal threshold
Kent	109	10% + 2mph
Lancashire	34	10% + 3mph
Leicestershire	30	10% + 2mph
Merseyside	18	10% + 2mph
Metropolitan Police/TfL	805	10% + 3mph
Norfolk	26	10% + 2mph
North Wales	28	10% + 2mph
Northumbria	55	10% + 2mph
Nottinghamshire	48	Refused to confirm if threshold exists
Police Service of Northern Ireland	12	10% + 2mph
Scotland	173	Refused to confirm if threshold exists
South Wales	137	10% + 2mph
South Yorkshire	25	10% + 2mph
Staffordshire	286	Would not reveal threshold
Suffolk	4	10% + 2mph
Thames Valley	294	10% + 2mph
Warwickshire	28	10% + 2mph
West Mercia	23	10% + 2mph
West Midlands	33	Would not reveal threshold
West Yorkshire	402	10% + 2mph

Speaking about the findings, AA President Edmund King said: “Auto Express's testing is a valid reminder to drivers not to gamble on their speedo perhaps providing some leeway.”

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