The A 45 AMG is a very fast hot hatchback. Having spent a good 150 percent of what you might call the going rate for such a car, owners would expect nothing less.

They might reasonably expect this to be the fastest car of its kind ever produced, full stop. In the past, we’ve seen two premium-brand fast hatchbacks smash the prevailing class standard on 0-60mph acceleration: the Audi RS3 (4.5sec to 60mph) and the BMW M140i (4.6sec).

Matt Saunders Autocar

Matt Saunders

Road test editor
Despite its power, the engine meets Euro 6 emissions regulations

We clocked the Mercedes-Benz at an impressive 4.2sec, set on the same piece of asphalt in similar circumstances, so there's no question about its competitiveness. Underneath it all, this is undoubtedly the new performance king of the class.

The A 45 whistles and growls from 50mph to 100mph almost a second quicker than either the Audi or the BMW. It’s the only hot hatchback we’ve ever figured that hit 150mph inside a standing mile on MIRA’s dead-level horizontal straights.

Between incredible traction, formidable mid-range torque and an unrelenting delivery at high revs, it’s nothing short of a monster and has as much performance as you could ever sanely deploy on the road.

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Aside from the occasional refusal of the paddle-shift gearbox to do what it’s told, we have only one other criticism here. Although it’s damned effective at what it does, the four-cylinder engine lacks a little bit of vibrancy, compared with the kind of performance motors available at this price.

Over-dramatised gearchange pops compensate little for the fact that a BMW straight six or a Porsche boxer engine offers so much more character.

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