The BMW Brutus Experimentalfahrzeug (experimental vehicle) will not sit well with the Prius contingent - its 46-litre V12 only manages 0.18mpg - but, as Richard and Jeremy agreed on Sunday, it is unequivocally glorious.
Firstly, the engine. After World War I, Germany was forced to disarm under the Treaty of Versailles, which meant there were a few plane engines knocking around. And in 1925, one of them found its way into BMW's hands.
BMW then slapped it onto a 1908 American-LaFrance chassis for use as a racer. After much tinkering, it rolled out of the workshop later that year in all its lethal chain-driven, leaf-sprung glory. On account of its 12-cylinder, 46-litre engine and gently terrifying looks, the BMW techs christened it Brutus.
And it's the meeting point for some preposterous numbers. It'll chew through 6.5 gallons of fuel over a 1.2-mile sprint - that's 0.18mpg - and kick out around 28,000g/km of C02. That's slightly more than 282 VW Polo Bluemotions.
As for power, there's lots of it. And it's really firey (click below to watch the world's most ludicrous barbeque). It produces 493bhp at just 1500rpm, and can pull 62mph at a paltry 800rpm.
Want to see it in action? It'll be running up the hill at this year's Cholmondeley Pageant of Power, which is held between July 15 and 17.
Have you seen a more bonkers racer, TopGear.comists?