Aston Martin has revealed that its new 430bhp Cygnet, a one-off model from Aston Martin's Q commission service, will be one of two new models from the legendary British sports car manufacturer on display at this weekend's Goodwood Festival of Speed in the U.K.

Longstanding observers of the motor industry might remember that between 2011 and 2013, Aston Martin was producing a city car to meet EU fleet emissions regulations. The regulations stated a manufacturer's range was only allowed to produce average emissions below a certain level, so the Cygnet was produced to get Aston's average emissions down. Well, Aston has finally produced another version of the Cygnet city car, but with a 430 bhp V8 engine under the hood, there doesn't seem to be a lot of concern about its emissions.

Along with the 715 bhp DBS Superleggera, the Cygnet, described by Aston Martin as "the ultimate city car," will be making its public debut at the event. The very unusual Aston was built at the request of one of the company's customers, and its most outstanding feature is a 4.7-litre V-8 engine producing 430 bhp, taken from the previous generation of the Vantage S.

Cygnets produced previously by Aston Martin were based on the Toyota IQ and had an engine that was a full 3.4-litres smaller than the unit in this new one-off, producing a staggering 333 horsepower less than the one appearing at Goodwood this weekend. This Cygnet will be faster than the outgoing V8 Vantage as the little car is capable of a 170 mph top speed and boasts a 0 to 60 mph time of 4.2 seconds. Even so, most people would probably have expected a little more for a city car with a 4.7-litre V-8 under the hood as that's only about the same that the current Volkswagen Golf R with a DSG gearbox can deliver.

To fit that engine into the car's very compact proportions a new front bulkhead and transmission tunnel had to be specially fabricated from sheet metal, and the suspension and subframe are partly shared with the previous-generation Vantage that loaned its engine to the Cygnet. All of that, along with a twin-exhaust and full roll cage, means the Cygnet weighs in at a pretty substantial 1,375 kg, which is probably why the Cygnet isn't significantly faster than it actually is.