Revealed: Britain's least economical cars
Honest John, the website and not the man in the hat, has issued a press release that reveals Britain's most economical cars. Small petrol and diesel cars, hybrids, plug-in hybrids – the sort of cars that are one step up from buying a bus pass.
Some of the figures are quite impressive. Take the Suzuki Celerio, which can deliver 70.2mpg, according to Honest John's Real MPG data, making it the most economical petrol car you can buy. Fancy a diesel? A Nissan Micra dCi 90 could return 69.6mpg if you drive with due care and attention.
Unsurprisingly, few of the cars on Honest John's list will be triggering the heart rate app on your smartwatch. There are a few exceptions, like the BMW 740e (74mpg) and Volvo V60 D5 plug-in hybrid (80.2mpg), but the majority are the sort of cars driven by people who don't like cars.
However, at the bottom of the page you'll find a list of the least economical cars, and that's where things start to get interesting. Aaaaand in at number one on this week's Top of the Pumps is the Mercedes-Benz C63 AMG Coupé and its Real MPG figure of 17.5mpg. Ouch.
It has, according to Honest John sans hat, ‘an engine that sounds angrier than a whole month's worth of EastEnders episodes’. A nice line, HJ; Petrolblog doffs its trilby to you.
Without further ado, here are the least economical cars. Make sure you've got a Shell loyalty card if you're buying one of these eco worriers.
- Mercedes-Benz C63 AMG Coupé (2011-2016): 17.5mpg
- Mercedes-Benz ML63 AMG (2012-2015): 17.7mpg
- Range Rover Sport 5.0 V8 Supercharged (2013-2022): 18.7mpg
- Audi RS5 (2010-2016): 18.3mpg
- BMW X5 M (2014-2018): 18.3mpg
- Mercedes-Benz CLS63 AMG (2011-2018): 19.2mpg
- Aston Martin Vantage V8 (2005-2018): 19.2mpg
- Nissan GT-R (2009-2022): 19.9mpg
- BMW M6 Gran Coupé (2012-2018): 20.4mpg
- Mercedes-Benz E63 AMG (2009-2016): 21.1mpg
For more information, check out Honest John's best Real MPG cars of 2025.
