Running costs
UK Car Insurance Groups Explained: 1 to 50 Checker Guide
Insurance groups are the single largest benchmark underwriters use to calculate vehicle premiums. Here is how Thatcham Research assigns groups 1 to 50, what the security suffixes mean, and which cars are cheapest to insure.
What is a car insurance group?
In the United Kingdom, every vehicle model and trim level is assigned an official insurance group rating from 1 to 50. Managed by the Group Rating Panel administered by Thatcham Research alongside the Association of British Insurers (ABI), this standardised system evaluates the financial risk associated with repairing, replacing, or insuring that specific vehicle.
How Thatcham Research calculates groups
The Group Rating Panel analyses several core mechanical, financial, and structural factors before awarding a rating:
- Damage and repair costs: Thatcham conducts standard 15 km/h front and rear impact crash tests to calculate the physical damage sustained and the exact cost of replacement parts and labour.
- Parts pricing and availability: The cost of a standard basket of 23 common replacement parts (bumpers, headlights, windscreens, radiators, wings) is benchmarked against rival brands.
- Repair times: How long standard repair operations take according to manufacturer procedures.
- Vehicle performance and acceleration: 0 to 60 mph acceleration times and top speeds are evaluated; faster cars have statistically higher accident severity rates.
- Bumper compatibility: Alignment of bumper beams with standard crash barriers to minimise under-ride damage during minor collisions.
- Autonomous Emergency Braking (AEB): Modern Advanced Driver Assistance Systems (ADAS) that prevent low-speed shunts can significantly reduce a vehicle's group rating.
Insurance security suffixes (A, E, D, U)
Alongside the number, every car is awarded a security rating letter that reflects its factory-fitted anti-theft systems (immobilisers, deadlocks, alarm sirens, and glass etching):
UK insurance group security letter definitions
| Letter suffix | Security standard | Impact on insurance group |
|---|---|---|
| E (Exceeds) | Exceeds standard security requirements for this category | Often lowers the final insurance group rating (e.g. Group 12 becomes 11E). |
| A (Acceptable) | Meets standard Thatcham security baseline | No change to the standard numerical group rating. |
| D (Deficient) | Falls below security requirements for this vehicle class | Increases the numerical group rating due to higher theft vulnerability. |
| P (Provisional) | Incomplete test data available at vehicle launch | Provisional rating until full assessment is finalised. |
| T (Tracker) | Factory-installed Thatcham-approved GPS tracking system | Required or advantageous for high-risk vehicles in Groups 40 to 50. |
| U (Unacceptable) | Security falls significantly below minimum standards | Underwriters may refuse cover or require aftermarket alarm installation. |
Lowest insurance group cars in the UK
For new drivers, students, or motorists wanting to cut annual motoring costs, selecting a car in Insurance Groups 1 to 5 delivers the lowest baseline quotes:
Examples of popular low-insurance vehicles in the UK
| Make & model | Engine & trim | Typical group | Key benefit |
|---|---|---|---|
| Volkswagen Up! | 1.0 MPI (60 PS) Take Up | Group 1 | Low repair costs, high AEB safety rating. |
| Skoda Citigo | 1.0 MPI (60 PS) S / SE | Group 1 | Shares Up! platform with cheap parts pricing. |
| SEAT Mii | 1.0 MPI (60 PS) Ecomotive | Group 1 | Economical 3-cylinder engine, low repair times. |
| Hyundai i10 | 1.0 MPi (67 PS) S / SE | Group 1 to 2 | 5-year warranty, reliable mechanicals. |
| Kia Picanto | 1.0 DPi (66 PS) 1 | Group 1 to 3 | 7-year warranty, compact urban dimensions. |
| Ford Fiesta | 1.1 Ti-VCT (70 PS) Trend | Group 2 to 5 | Extremely widespread replacement parts availability. |
| Vauxhall Corsa | 1.2 (75 PS) Design | Group 3 to 6 | Low repair costs and modern driver assistance tech. |
Overview of groups 1 to 50
How different vehicle classes map across the 50 insurance groups:
- Groups 1 to 10: City cars, small superminis, low-output engines. Best for young and first-time drivers.
- Groups 11 to 20: Family hatchbacks, compact crossovers, and mid-range saloons (e.g. Ford Focus, VW Golf 1.5 TSI, Nissan Qashqai).
- Groups 21 to 35: Executive saloons, hot hatchbacks, mid-size SUVs, and entry-level luxury brands (e.g. BMW 3 Series, Audi A4, VW Golf GTI).
- Groups 36 to 50: High-performance sports cars, high-value prestige SUVs, luxury EVs, and supercars (e.g. Range Rover, Porsche 911, Tesla Model S, BMW M3).
Check vehicle specs & history
Before purchasing a used vehicle, check its full engine specifications, MOT history, tax status, and provenance with Caroat's free vehicle check.
FAQ
What are UK insurance groups and how do they work?
Every car sold in the UK is assigned an official insurance group rating from 1 (cheapest to insure) to 50 (most expensive to insure) by Thatcham Research on behalf of the Association of British Insurers (ABI). The rating evaluates repair costs, parts pricing, vehicle performance, body shell complexity, security features, and safety technology.
What cars are in Insurance Group 1?
Insurance Group 1 contains the cheapest cars to insure in the UK, making them ideal for new, young, and budget-conscious drivers. Typical Group 1 cars include entry-level city hatchbacks such as the Volkswagen Up! (1.0L 60PS), Skoda Citigo, SEAT Mii, Hyundai i10 (1.0L S), Kia Picanto (1.0L 1), and Chevrolet Spark.
What do the insurance group security letters (A, D, E, P, T, U) mean?
Each insurance group number has a security suffix: 'E' indicates the car exceeds security requirements (often resulting in a lower group rating); 'A' means standard acceptable security; 'D' indicates security falls below requirements; 'P' indicates provisional rating; 'T' indicates vehicle tracking is fitted; and 'U' indicates unacceptable security for that category.
Does an engine modification change my insurance group?
Yes. Any performance enhancement, remap, exhaust alteration, or body modification can void standard group ratings and must be declared to underwriters, who will assess risk individually rather than using standard ABI group tables.
How can I check the insurance group and specifications of any car?
You can enter any UK registration plate on Caroat to check complete vehicle specifications, engine capacity, power output, fuel type, and running costs before requesting insurance quotes.