The wraps are finally off Nissan's ultimate GTR, a custom-built ultracar that's all yours - if you have the ludicrous cash to buy one.

The Nissan GT-R50 has been dreamed up and designed by Italdesign and it made its world debut at the Goodwood Festival of Speed yesterday (July 12).

As the first collaboration between Nissan and Italdesign, the prototype is being tipped as the blueprint for an extremely limited run of hand-built production vehicles which will mark the 50th birthdays of both the GT-R, in 2019, and Italdesign, this year.

Alfonso Albaisa, Nissan's senior boss of global design, says the car "combines power and artistry to celebrate 50 years of inspiring the dreams of our customers" and a customer version will be created, pending reception at Goodwood. Prices, he says, are estimated to start at

Pending the GT-R50 by Italdesign's reception at Goodwood and other global appearances in the coming months, a customer version inspired by the prototype may be created. No more than 50 units would be produced by Italdesign - with each car tailored for each customer - with a price estimated to start at about £800,000.

If you're still reading, you do get a lot of interesting stuff for the cheque. For a start, there's the body: "combining brute force with Italian craftsmanship and tailoring," says Nissan. Yep, seems fair. Key features include a pronounced power bulge on the hood, stretched LED headlights, a lowered roofline, and prominent "samurai blade" cooling outlets behind the front wheels. A large, adjustable rear wing, mounted with two uprights, completes the overall look. The exterior is finished in "liquid kinetic" grey, with distinctive gold anniversary accents.

And underfoot? A special power plant boasts up to 120PS over the stock engine. Drawing on Nissan's extensive GT3 racing experience, the NISMO organisation enhanced the hand-assembled 3.8-litre V6 VR38DETT to produce an estimated 720PS and 780 Nm of torque. A revised Bilstein suspension damping system and upgraded Brembo braking system help handle the extra power.

Nissan has given out a website address for enquiries, but states they need to be "serious".