The yacht has a sauna, gym and a 600-bottle wine cellar

The Mirabella V was the final vessel to be built by VT - formerly known as Vosper Thornycroft - at its shipyard in Woolston, Southampton.

The single-masted 246ft-long yacht cost more than �30m to build and will be hired out for about �135,000 a week.

It will sail in the Caribbean and the Mediterranean and only needs to be used for 20 weeks a year to break even.

Owner Joe Vittoria, former head of Avis Car Rentals, said: "This totally pushes the envelope. I mean there isn't a mast this size, there isn't a hull of this size, so we've pushed everything beyond the normal limits.

"It's a gamble but in sail boats there is clearly a passion involved, you're not going to do this unless you're passionate.

"This has been my life. I've invested a lot in this boat and I believe in it."

Shipbuilders at VT Group's yard in Portsmouth are going over the final checks ahead of her maiden voyage to Naples at the end of next week.

The vessel, which is twice as tall as Nelson's Column, houses a sauna, gym, jacuzzi, plunge pool, dining area and a 600-bottle wine cellar.

There is also room for 12 crew, 12 guests and jet skis.