Aston Martin's One-77 supercar has exceeded 220mph (354km/h) in testing, the company has revealed – making it the fastest road-going Aston ever.

The One-77 is currently undergoing high speed testing at a proving ground in southern Europe, believed to be the 7.8-mile Nardò facility in Italy.

According to Aston Martin the One-77 recorded a top speed of '220.007mph (354.86km/h)', though that remarkably neat 220.007mph figure actually translates to 354.07km/h. Whatever the top speed actually was, Aston Martin says it was set in dry but windy conditions during a series of test runs last week.

The One-77 is powered by a newly-developed 7.3-litre version of Aston Martin's V12 engine, which powers the V12 Vantage, DB9, DBS and Rapide models. The One-77's top speed suggests that the new engine produces around 730bhp.

Deliveries of the One-77, which will be limited to 77 individually numbered examples, are expected to begin in mid-2010.