It’s hard to believe Ariel Motor Company has just turned a quarter of a century old. It doesn’t feel like five years have passed since the firm introduced its groundbreaking exoskeleton Atom, yet it’s already on its fourth generation. Perhaps that’s because the car has always looked so futuristic and otherworldly.

In order to celebrate, the Somerset-based firm has announced its most powerful model to date, the Atom 4RR. The new car produces a frankly bonkers 525bhp and 550Nm from a bespoke version of Honda's turbocharged 2.0-litre four-cylinder engine, commonly found in the snout of the Civic Type R. Extensive engine modifications, including revised internals and upgraded oil and fuel systems, contribute not only to generating the power, but sustaining it.

Ariel says the full details of the car – including pricing – will be revealed later in the year. But given the existing 4R weighs a mere 595kg and can reach 100mph from a standstill in under 6.5 seconds equipped with 400bhp, expect the 4RR’s performance to be suitably explosive. Appropriately, the car will be limited to just 25 units, all built to order.

Being the firm's fastest-ever car, the 4RR remains road-legal but is primarily engineered with circuit performance in mind. It represents the latest evolution of a lineage that began in 2000 with the Rover K-series-engined Atom, which introduced Ariel's trademark exoskeletal chassis and minimalist design ethos.

Subsequent iterations saw the Atom 2 adopt Honda power – somewhat of a coup for the small British firm – while the Atom 3 introduced a revised chassis and supercharged variants. Next came the ‘inbetweener’ Atom 3.5, a heavily revised car incorporating further refined suspension and engine management.

The Atom 4 was the most radical departure. Launched in 2018, it marked the first use of turbocharging in the model line and brought substantial chassis, geometry and electronics updates.

While Ariel has built motorcycles and e-bikes in recent years, the Atom remains the brand's flagship, known for its extreme power-to-weight ratio and raw driving experience.

The 4RR isn’t the first time Atom has created a car to celebrate a landmark. In 2010, the firm created the outlandish Atom V8 by fusing a pair of Suzuki Hayabusa motorcycle engines together – resulting in 500bhp at 10,600rpm – to commemorate a decade of production. At the time, Ariel boss Simon Saunders said, ‘In 10 years you might not be able to do this sort of thing any more.’ With the 4RR, that premonition has been emphatically disproven.