Illegal car modification hotspots revealed

Gloucestershire has the highest proportion of illegal car modifications, with altered number plates the most common breach

Volkswagen Polo exhaust

The areas of the UK with the highest proportion of illegal car modifications have been revealed, with Gloucestershire topping the list.

The county with a population of 637,100 saw 925 offences in 2020 - equivalent to 1,452 per million people. Norfolk, where 907,800 people live, saw 1,127 offences - equivalent to 1,241 per million people, placing it second on the list. Third was Northern Ireland, with 1,179 per million people.

Rank

Area

Total offences

Offences per million people

1

Gloucestershire

925

1,452

2

Norfolk

1,136

1,251

3

Northern Ireland

2,232

1,179

4

Suffolk

873

1,147

5

London

9,373

1,047

6

Surrey

930

777

7

Northamptonshire

501

665

8

Dyfed-Powys

320

616

9

Greater Manchester

1,518

535

10

Leicestershire

494

449

Data from 36 UK police forces acquired by Compare the Market via a freedom of information request placed Gwent at the bottom of the list. The Welsh county, with its population of 594,200, saw only four illegal car modifications in 2020, equivalent to seven per one million people.

The 1,161,100-strong county of Nottinghamshire saw 54 offences in total - 47 per million people - while Cambridgeshire’s stats, with its population of 855,800 had 47 offences, equals 55 per million people.

The most common illegal vehicle modification detected by police is the alteration of a number plate - 13,720 such offences occurred in the UK last year, making up 56 per cent of total illegal vehicle modifications. Illegally altered lights made up 23 per cent, while illegally tinted windows accounted for 17 per cent.

Rank

Modification

Total offences

Percentage of total offences

1

Altered number plates

13,720

56 per cent

2

Altered lights

5,723

23 per cent

3

Illegally tinted windows

4,183

17 per cent

4

Altered exhausts

776

Three per cent

Dan Hutson, head of motor insurance at Compare the Market, commented: “Modifications tend to fall into two categories - performance or cosmetic - but any modification, no matter how minor, should be reported to your car insurance provider. 

“Lawful modifications can increase car insurance premiums, so it’s best to check with your provider before making any changes, and there are some providers who specialise in modified cars. Modifications which are against the law are likely to invalidate any type of car insurance policy, so do your research beforehand.”

Check out our guide to engine mapping and car chipping

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