HUNDREDS of Hampshire workers who built the world's largest private yacht can now breathe a sigh of relief - she is more or less ship-shape.

Mirabella V, the £35m dream of multi-millionaire Avis hire car magnate Joe Vittoria, yesterday left Portsmouth for sea trials in the Solent.

The 740-tonne sloop, available to hire from £145,000 a week, was made by VT Group at the company's former shipyard at Woolston, Southampton.

Maritime experts say it was the most ambitious shipbuilding project of its type because the use of space-age materials required complex construction methods. Mirabella V, with a record-breaking 95-metre high mast that would dwarf Nelson's Column, was due to be used by super-rich guests from last summer.

However, the 75-metre long super yacht was dogged by delays and escalating costs caused by technical hurdles.

Now, however, the final touches are being undertaken so she can be ready to visit the millionaires' paradise of Monte Carlo for the Monaco Grand Prix in the south of France on May 23.

Mr Vittoria, who worked closely with designer Ron Holland on the breath-taking pet project, was unfazed by the budget going over by at least £5.4m. "It is immaterial to me," he said.

Mirabella V, which unfurled her 1,557-metre square sail for the first time this week, can race through the seas at up to 20 knots.

She has been based at VT Group's £50m docks at Portsmouth, and there was a scare a few weeks ago when workers noticed a small crack in the keel. That was put right, and she is now expected to be the luxury plaything of the world's super-rich and famous, such as Hollywood director Steven Spielberg and Pulp Fiction actress Uma Thurman.