2023 Reliability Survey: Britain’s most and least reliable …

How the research was carried out

The What Car? Reliability Survey is open to everyone who visits whatcar.com or subscribes to What Car? magazine. Responses were received from car owners around the UK. 

We ask them to tell us if their car had suffered a fault in the previous 24 months, and if so what area of the car was affected. We then ask them to expand on this by telling us how much they had to pay to get the fault fixed and how long their car was in the workshop. 

We use the information to create a unique reliability rating for each model and brand where we have a large enough response rate. These two factors are more important than how many faults a car suffered, because they determine how much inconvenience and expense a problem caused.

The information about where faults occurred adds depth to our data, with us asking car owners to pick from one of 14 different categories: air-con, battery, bodywork, brakes, engine or motor, engine or motor electrics, exhaust, fuel system, gearbox/clutch, interior trim, non-engine or motor electrics, sat-nav/infotainment, steering and suspension.

This year, we have data for 178 models (up to five years old) from 32 brands. Where we have a large enough sample size, we separate petrol, diesel and hybrid versions of each model to provide the most detailed analysis of car reliability.

The top 10 most reliable cars

=1. BMW 1 Series (2011-2019)

Reliability rating 100%

This version of the 1 Series is no longer on sale new, but it's worth searching for a secondhand example if you want a dependable car, because not a single 1 Series owner who responded to our survey reported any glitches with their car, making it a great model to live with. Our data includes petrol and diesel-engined models and owners told us both fuel types were fault-free.