Small Engine, Long Shadow

Four hundred and forty kilograms is the published kerb weight of the Caterham Seven 170, the lightest car the company has built. Its engine is a 660cc turbocharged three-cylinder from Suzuki, rated by Caterham at 84 bhp and 116 Nm. It reaches 60 mph in 6.9 seconds and the price starts at £29,490. Every figure in that sentence is ordinary except the first, and the first is the one that does the work.

Mass is the tax levied on every other decision in a car. Reduce it and the brakes can be smaller, the tyres narrower, the springs softer, the engine less powerful and the fuel bill lower, all at once and without a single clever component. It is the cheapest performance available to an engineer, and the volume industry has spent thirty years walking away from it. Four British companies have not. They sit in Kent, Worcestershire, Somerset and Norfolk, and their scale is better understood from the payroll than from the horsepower.

Caterham Seven 170 440 kg

Ariel Atom 600 kg

Morgan Super 3 (dry) 635 kg

Morgan Supersport 1,170 kg

Mean new car, Autocar road tests 2023 1,947 kg

Lotus Eletre R 2,640 kg

Morgan quotes the Super 3 as a dry weight; the rest are kerb weights. The 1,947 kg figure is the mean for cars Autocar road-tested in 2023, not the whole UK market.

Source: Caterham, Morgan, Hagerty UK, Motoring Research, Autocar and evo, 2023–2026

The Kei Car From Kent

The Seven 170 is named for its power-to-weight ratio, which Caterham puts at more than 170 bhp per tonne. Its Suzuki engine was drawn for the Japanese kei class, where displacement is capped at 660cc, so it arrives in Kent already small. Nothing else about the car is unusual by Caterham standards. The arithmetic is what changes: a car this light does not need a big engine to be quick, and a small engine does not need a big car to carry it.

The factory is the more interesting story, and it did not go where the rumours said. When evo visited in March 2025 it found Caterham settled into a new Dartford building of 54,000 sq ft with a further 30,000 sq ft of mezzanine, a £3.5 million conversion, and 33 individual production bays run on a one man, one car basis rather than a moving line. Output was then around 500 cars a year against a target of as many as 750. Project V, the electric coupé Caterham has been promising, was not part of that plan: development had gone to Tokyo R&D in Japan, Yamaha had been named as the e-axle supplier, and VT Holdings, Caterham’s owner, was still seeking the funding to build it in a plant of its own.

Malvern, Without Interruption

Morgan was founded in 1909 and still builds cars at Malvern in Worcestershire. Its cheapest model is also its lightest. The Super 3 is a three-wheeler with a dry weight of 635 kg and a 1.5-litre naturally aspirated three-cylinder Ford engine making 118 bhp, which is enough for 0–62 mph in 7.0 seconds; it costs £39,995. At the top of the range the Supersport uses a turbocharged 3.0-litre BMW straight-six and weighs 1,170 kg, light for that performance and heavy for a Morgan. It starts at £102,000 and the company plans to hand-build about 180 a year.

None of which is a licence to print money. Accounts reported by City AM in October 2024 showed Morgan’s turnover rising from £41.7 million to £48.9 million across 2023 while the pre-tax loss widened from £15.5 million to £25.5 million. UK turnover fell to £16.2 million over the same year; European turnover rose to £24.8 million. Morgan has been majority-owned by the private equity firm Investindustrial since 2019.

We aren’t trying to make a direct rival for the 911. But we do want to offer a credible alternative.

Thirty People In Somerset

Ariel Motor Company is the smallest of the four and the most instructive. Hagerty UK went to Crewkerne in March 2023 and found 30 employees aiming at 100 cars and roughly 30 motorcycles a year. Each car takes between 140 and 160 hours, is assembled in a bay by one person, and is signed by whoever built it. Hagerty put the Atom’s weight at 600 kg. There is no line to balance, no shift pattern to disrupt and no volume target to miss.

A lot of people are obsessed with growth. We have not grown in 10 years.

What Hethel Is Now

Lotus is the cautionary case, because it is the British company that made lightness famous and the one that has travelled furthest from it. Hethel still builds the Emira, the last combustion Lotus. The showroom also holds the Eletre, an electric SUV with a 112 kWh battery: evo’s test published in January 2025 recorded 2,640 kg for the 905 bhp Eletre R, with the range priced from £89,500 to £166,595. Six Caterham Seven 170s weigh the same as one of them.

Then the arithmetic arrived. PistonHeads reported on 29 August 2025 that Lotus had confirmed a further 550 redundancies, most of them at Hethel, taking a site that claimed around 1,300 workers to fewer than 1,000. The company pointed to rapid changes in global policy, tariffs among them. The factory itself survived, which is not the same as thriving.

While any job losses are concerning, it is important to recognise the worst-case scenarios, fairly recently on the table, have been avoided: that being the complete closure of the factory.

Everything Else Got Heavier

Sample	Mean kerb weight
All cars tested, 2016	1,553 kg
All cars tested, 2023	1,947 kg
Battery-electric cars tested, 2023	1,991 kg
All cars tested, first quarter 2024	2,087 kg

Source: Autocar road-test data, reported by ATF Professional, 2024

That table carries a caveat and deserves it. The analysis, published in August 2024, covers the cars Autocar chose to road-test rather than every car registered in Britain, and test fleets skew towards the large and the expensive. The direction is not in dispute. Nearly 400 kg went on in seven years, battery-electric cars tested in 2023 averaged 1,991 kg, and the only vehicle under 1,000 kg that Autocar tested that year was the Citroën Ami, which is legally a quadricycle rather than a car.

Small Is Now A Legal Category

Regulation has quietly turned in the specialists’ favour. Under the revisions to the zero emission vehicle mandate announced in April 2025, manufacturers registering fewer than 1,000 cars a year are exempt from the 2030–2035 requirements outright, while those registering between 1,000 and 2,499 will negotiate individual CO2 reduction targets instead of meeting the general one. Magneto listed Morgan, Caterham, Ariel, Aston Martin, McLaren and Lotus among the beneficiaries. Note what is being rewarded: the exemption is for being small, not for being light. A 440 kg petrol car and a 2,000 kg one are treated identically provided few enough leave the gate.

Which is the frustration buried in all of this. The specialists’ case is not nostalgia and it is not about lap times. A car that weighs 440 kg needs less battery, less brake, less tyre and less road than one weighing 2,640 kg to do the same job, and every gram it never carries is a gram nobody had to mine, ship or eventually recycle. The physics is sitting in plain view in Kent, Worcestershire, Somerset and Norfolk. Thirty people in Crewkerne are still doing the sums by hand, one car at a time, and signing their work when they finish.