It’s a label – and Andy understood labels better than anyone.”Mr Macaulay agrees: “When you see the portraits of Marilyn Monroe, you think of Warhol before you think Monroe. He is so associated with the mid-20th century that the popularity of his work will certainly last.”The original paintings are the most valuable. One of Mick Jagger sold recently for $150,000, while one of Monroe fetched $17.5m. His first Campbell’s Soup series, which originally went on the market in 1961-62 for $200, didn’t sell at the time. Later, they went for for $37m.Even Warhol-related items could be worth investing in. Christie’s has a poster from an exhibition at the Tate in 1971, signed by the artist, for sale this week: it is expected to fetch £500 to £700.

A couple of designs for the jacket of his book The Philosophy of Andy Warhol, which he also signed, have an estimated value of £1,500 to £2,000.As with most collections, aim for the best-quality prints when investing in Warhol’s works. “The condition of the prints that come up for sale varies a lot,” says Ms Harris. “But if you get one in good condition, you’ll know you have an original graphic work by an artist who was a master printer.”WARHOL’S WORKS PricesFrom £500 for a Warhol-related item to over £20m for an original painting of an icon.More information Christie’s, ; Sotheby’s, co.uk; the Andy Warhol Museum, ; – a website dedicated to the artist.2004 events 30 June: Pop Art 1954-1974, Christie’s, London. That caused Mr Moore to cry “censorship”, generating valuable publicity just before Fahrenheit 9/11’s triumphant world premiere at the Cannes film festival, where it won the Palme d’Or.. The same was true in Fayetteville, North Carolina, home of the US Special Forces at Fort Bragg. The film even did well in the twin cities of Midland and Odessa in west Texas, where President Bush spent his formative years.These are the places where it might really change minds, acting as an extended political advertisement for which John Kerry, President Bush’s Democratic Party challenger, will not have to pay a penny.The box-office figures were a vindication for Mr Moore and his immediate backers, the Weinstein brothers of Miramax, who bought the film back from Miramax’s parent company, Disney, after Disney refused to distribute it. It sold out in Peoria, Illinois, famously regarded as the quintessential bellwether city where party registration splits 50-50 between Democrats and Republicans.

On the coasts and in the larger university towns, Fahrenheit 9/11 largely played to the choir, who cheered, clapped and laughed as Mr Bush was portrayed as a distracted ideological butterfingers.Many of the crowds were called out by MoveOn , a liberal website cheerleading for Mr Moore for weeks, who last night set up a conference call with the film-maker at an estimated 2,000 member-attended house parties.But the film also did well in communities where political affiliations are more evenly split. The number one film in the United States yesterday was Fahrenheit 9/11, Michael Moore’s relentlessly publicised counterblast against the Bush administration. Sell-out crowds across the country broke box-office records for a political documentary. In New Hampshire and West Virginia, which also went Republican, Mr Nader’s votes may have cost Mr Gore victory.Mr Nader won 2.7 per cent of the popular vote in 2000 This year some polls show his support at up to 6 per cent.. He faces a state-by-state battle to collect enough signatures to qualify.Making matters trickier still, the Democrats have signalled they will use every legal avenue to thwart the man who many Democrats believe cost Al Gore the White House four years ago, and who could do that to John Kerry in 2004.Last time, Mr Nader won 97,488 votes in Florida, which George Bush took by 537 votes. But the party has nominated the Texas lawyer David Cobb, turning its back on Mr Nader and his running mate, Peter Camejo.Now Mr Nader will find it harder to get on the ballots in 22 states and the District of Columbia where the Green party already has a slot on the ballot.