One of the world’s leading experts on Leonardo da Vinci has said a delay in exhibiting Salvator Mundi, the world’s most expensive painting, is not due to questions about its authenticity.

The art world went into a spin when it was revealed last month that the Louvre Abu Dhabi had indefinitely postponed putting on display the painting bought for a world record price of $450.3m (£342.1m) last year.

Because its authenticity has been the focus of so much speculation, experts had wondered whether there may be new revelations to come about whether or not it is definitely a Leonardo.

Martin Kemp, a Leonardo scholar, told Cheltenham literature festival: “I am convinced, for reasons I won’t go in to, that when people said it was because of doubts about the attribution, that’s not right.”

It will, he claimed, go on display at the Louvre in Paris next October to mark the 500th anniversary of Leonardo’s death. “Next year is going to be crazy, and great fun.”

The painting is officially owned by the Council of Tourism and Culture in Abu Dhabi and Kemp said there was secrecy at the highest level. “Getting information out of Saudi Arabia is very difficult.”

But he remains just as convinced as ever that it is a genuine Leonardo. It fetched such a staggering price because its buyers wanted the magic of Leonardo. “It is a price for something beyond being a work of art,” he said. “In a sense it is outside the scale of works of art which have got more and more expensive.”

Among the reasons Kemp is convinced the painting is genuine is the hair. Followers could do curls of hair quite well, “but you look at Leonardo’s curls, or how he handles twisted drapery, he understands the physics of it. He understands the anatomy of the phenomenon. In the Salvator Mundi, there are some wonderful curls.”

Kemp, emeritus professor of the history of art at Oxford University, has spent decades studying Leonardo and has become one of the world’s leading authorities on him but he admitted there were examples he could not have on his own walls.

“I wouldn’t choose to have the Mona Lisa conspicuously in my house,” Kemp said. “It has a living presence that was slightly weird.” He continued: “Leonardos have that quality to them and Salvatore Mundi … I certainly wouldn’t want that looking at me. I’ve got a very brilliant full-scale reproduction of it but I put it in a corridor so I can walk past.”

Kemp said the “very intense” St John the Baptist was another example of a Leonardo painting that was “deliberately unsettling”.

The work he would love to have would be The Lady With an Ermine. “Absolutely wonderful … suave, sophisticated picture. It is painted in a simpler more traditional technique and the ermine is just wonderful,” he said.