Never mind the £100m tag – these Titians are priceless

"It will be tough. But I believe we can do it. And I'm determined we shall." Nicholas Penny, director of the National Gallery, is in steely, fighting form.

Anyone who has to raise £100 million to buy two paintings in an economic crisis being called the worst for 60 years is likely to suffer some discomfort, but he won't be deterred.

For Penny, these aren't any ordinary paintings but two of the greatest he's ever encountered. A world expert on Italian art, he has known these pictures, by Titian, all his life. They inspired him to devote his scholarly energies to the Venetian Renaissance. He speaks about them with passionate knowledge. Being able to stand close to the huge canvases — each nearly two metres square — and see this brushstroke, that tiny detail of a ghostly head, a glittering splash of water pouring from a jug, makes his pulse quicken.

The joint appeal, the first of its kind, was announced last week between the National Galleries of Scotland (NGS) and London to secure the two voluptuous Diana pictures for the nation. Part of the Bridge-water Collection of old masters owned by the Duke of Sutherland, the paintings have been on loan to the NGS since 1945.

The duke now wants to sell them for the favourable price of £50 million each. Last year they were valued at £180 million for indemnity purposes. Commercially they could fetch £300 million. Penny and his colleague John Leighton, director general of the National Galleries of Scotland, have until New Year's Eve to find cash for Diana and Actaeon and to come up with a strategy for financing Diana and Callisto within the next four years, with a first downpayment due on 1 January 2009.

Just days after the announcement of an urgent campaign to save the two Titians for the nation, Penny is amazed at the response. "What we hadn't bargained for," he says, "is the degree to which the public would want to help — people ringing up, emailing, asking at the information desk, looking for collecting boxes. We've been caught on the hop, still getting systems into place to deal with the cash. It's clear there's a huge wave of public support. It's extraordinarily heart-warming."

Painters from Lucian Freud to Tracey Emin have sung the praises of these paintings, and their centrality to art history. As long ago as 1922 the British government included Diana and Actaeon in its first "Paramount List" of key masterpieces in private collections which the Treasury agreed it would assist the National Gallery to buy, adding Diana and Callisto later.

At the same time, a noisy, anti-culture mob is baying for elitist blood. Ex-Sun ­editor Kelvin MacKenzie gave a representative view: "I don't want a plug nickel to be spent on anything until my house price is secure, my job secure, my children's education secure." He urged Lucian Freud "to give away some of the £50 million [Roman] Abramovich gave him for that fat bird if he likes them so much".

If MacKenzie's figures were muddle-headed, they do put the price of these masterpieces of the Italian Renaissance into stark perspective: the Chelsea FC owner paid £17.2 million for Freud's Benefits Supervisor Sleeping and, less than 24 hours later, £43 million for a Francis Bacon. In a day he had spent the price of a Titian on a couple of contemporary works which will take centuries to earn their place in the pantheon.
Would Penny accept a large cheque from a private patron? "We'd be mad not to consider it. This is a perfect opportunity for the Government to do what it's been discussing for so long: offer tax incentives for philanthropic giving. With four years of fundraising ahead, there's time to introduce that legislation."

Such reform would reduce, if not remove, the need to use such a slab of taxpayers' money. "What's so weird is that people never consider the total budgets spent on health or sport or defence — in comparison, spending on the arts is trifling. It makes no sense to say that

£100 million is the same as 100 yards of runway or a quarter of a footballer." Or, he might have said, around one per cent of the cost of London 2012.

This is Penny's first public challenge since he arrived in Trafalgar Square in February, from the National Gallery of Art in Washington, where he was senior curator of sculpture. His association with the National Gallery dates back to 1991. He was widely tipped to take over from Neil MacGregor when he left to run the British Museum in 2002. The appointment of 58-year-old Penny second time around met with almost unanimous acclaim.

In fact, Penny knew the two Titians were at risk even before he took the job. Given his field of expertise, it would be amazing had he not. It was he, after all, who identified the National Gallery's Madonna of the Pinks as a Raphael, saved after a public appeal in the time of his predecessor, Charles Saumarez Smith. Could it indeed be the reason Penny was ushered in so quickly?

"The [ex] chairman tipped me off," he says. "But it all had to be so secret that even the panel interviewing me didn't know it was likely to be an issue so quickly. The relief is that it's a joint enterprise, split 50-50 with Scotland. That's £25 million each by Christmas for the first picture, Diana and Actaeon."

He doesn't say "only £25 million" but it feels a more manageable figure put that way. There are indications that the Scottish Executive will contribute £10 million to £15 million. The DCMS, the Art Fund and the National Heritage Memorial Fund have also been approached. Penny's one surprise is that it has become partly a nationalist issue.

"As the son of a lawyer, I'm by instinct nervous of sharing things but here it's essential. One could argue that making such a deal is the downside of devolution, a smaller country being left to secure the treasures which make the National Galleries of Scotland world-class."

He adds: "I can't imagine anyone who loves great paintings not wanting to chip in and help. The Scottish Executive is showing signs of support and I would be surprised if Whitehall didn't feel the urge to match that — I desperately hope that they can."

The real struggle, Penny implies, will be the second stage of fundraising. "They're both miraculous paintings. Diana and Callisto is less well-known. These works have been called erotic, which I always find a bit disturbing, but in some sense they are. They seem to appeal to something fundamental in our being, with a sense of profound discomfort at the dramatic situations being exposed: Actaeon out hunting and stumbling upon the virgin goddess and her nymphs, or Diana pointing at the exposed belly of the pregnant Callisto. They're pictures that take you off balance."

The public benefit would be enormous: the paintings, always to be shown as a pair, would spend five years in Edinburgh and London in turn. Their purchase would also secure the continuing loan of 26 other Bridgewater masterpieces including works by Raphael, Poussin and Rembrandt.
Penny is unequivocal: this is the most important purchase of its kind in modern times. "I have made it clear that there's no bluffing here. Nothing like it can occur again ... "

Among the relatively few works that Titian painted on this scale, these two, part of a cycle for Philip II of Spain in the 16th century, are peerless masterpieces. To date the record price for an Old Master is £49.5 million, for a Rubens in 2002, though 19th-century and modern works have reached up to £70 million. Many would consider this imbalance with contemporary work a scandal. The Evening Standard's Brian Sewell considers the sum for the Titians "peanuts".
The National Gallery has no acquisition budget, relying on a significant endowment through its American Friends, an independent charity boosted by £50 million from philanthropist Paul Getty two decades ago. Their next meeting is in October. Getty's son, Mark, is now chairman of the gallery trustees.

Would the pictures be popular? That is not Penny's criterion. Though a pragmatist with a sharp business sense, he is one of the few cultural leaders to dare suggest visitor figures are not the chief concern of a museum. He has spoken out against blockbuster shows but with last year's National Gallery admissions of 4.1 million — before his arrival — showing a slight downturn, he has to be cautious.

"The obsession with attendance figures, without reference to the quality of the experience, is becoming as damaging as it is mad. The Hadrian show at the British Museum is not good because it sold thousands of tickets in advance but because it's good in itself. Sometimes we have to state the obvious."

One of the things that makes a country civilised, he argues, is its ability to educate people "to be aware of higher things in life, even if we don't necessarily enjoy them instantly. Why do parents suddenly start taking families to museums even if they themselves haven't been since they were the same age? It's because they want something better for their children".

For the 2012 Olympics, he reveals, the National Gallery will hold a major ­exhibition on dance across cultures and ages and art forms — "a celebration of physicality and athleticism but a non-competitive activity, usually anyway, which I think will be hugely popular".

Penny grins, a realist as well as an enthusiast. "Statistics aren't everything. Do we count the people who come into the gallery to use the lavatories or leave their rucksacks at the cloakroom? Do we track how many of them make it upstairs to look at a Titian? It begins to be insane. Where do they fit in to the equation, I'd like to know?"