The most expensive painting ever sold at auction, which has baffled the art world by disappearing from view after its record-breaking purchase two years ago, is hanging in the £400m superyacht of the ruler of Saudi Arabia, it has been reported.

Axar.az reports citing Dailymail.

Salvator Mundi, a depiction of Christ as saviour of the world, was painted in the early 1500s in the workshop of Renaissance master Leonardo da Vinci - although whether it is truly all Leonardo's work is itself a hotly contested topic.

The work broke all previous records at Christie's in New York in November 2017 when it was purchased by Badr bin Abdullah bin Mohammed bin Farhan Al Saud for $450,300,000 including fees.

Many at the time believed the Prince was acting on behalf of an even more senior member of the royal family: Mohammed Bin Salman, Crown Prince of Saudi Arabia, de facto ruler of the kingdom and arguably the most powerful man in the Middle East.

And it is to Bin Salman's yacht, the enormous Serene - which has a crew of 50, a helipad, and a submarine hanger - that the painting has now been tracked down, according to an art expert writing in ArtNet News.

The specialist publication reported that multiple sources, 'including two principals involved in the transaction', said the work had been 'whisked away in the middle of the night on MBS's plane and relocated to his yacht'.

It is the latest chapter in a turbulent history for the painting.

Sixty years ago it swapped hands for £45 as an undistinguished work in a job lot of Old Masters which had been collected by an English baronet.

In 2005, New York art dealers Alexander Parrish and Robert Simon bought it for $10,000 at a Louisiana estate sale.

Mr Parrish and a consortium he assembled then paid for it to be restored, with the work carried out by a leading figure in the art world, Dianne Dwyer Modestini, from New York University's Conservation Center of the Institute of Fine Arts.

Pre-restoration photographs show great white streaks running down the picture, and Christ with large patches of paint missing from his hair, chin, nose, forehead and left eye socket.

The painting has undergone extensive restoration in recent years, with its authorship repeatedly assessed and questioned until it was authenticated as a Leonardo in 2008 by a panel of art experts and sold for its record-breaking price tag in 2017.

But even now questions remain as to the painting's provenance.

Few of the doubters think Salvator Mundi is a modern fake. The original picture was almost certainly painted in Leonardo's lifetime (1452-1519).

We know that the pigments of the oil paints are the same as those used by Leonardo. And it was painted on a walnut wood panel — a surface he favoured.

But those doubters think it may be a 'workshop Leonardo': that is to say, it was painted in his studio but by one of his assistants.

At best, the master may have added the odd detail, they say, but it certainly isn't an 'autograph' painting — all Leonardo's own work — and therefore the mammoth price tag isn't justified.

Most damning may be a recent article which quoted the Metropolitan Museum of Art's Carmen Bambach saying she was wrongly referenced in Christie's catalogue as attributing the painting to the artist alone.

In fact Bambach stated that the work was mostly painted by 'Leonardo's assistant, Giovanni Antonio Boltraffio.'

Matthew Landrus, a Leonardo expert at Oxford University, suggests Salvatore Mundi is the work of da Vinci's assistant Bernardino Luini.

And a French expert, Jacques Franck, alleges that Louvre staff 'know that the Salvator Mundi isn't a Leonardo'.