Hilary Spurling's triumph at the Whitbread awards last night for her monumental biography of the modernist painter Matisse may have inspired a generation of budding writers to take up the biographer's art, but news from the other side of the Atlantic may give them pause for thought.

Donald Trump has issued a lawsuit against an author who dared to suggest that he was worth only $250 million. The amount Trump is suing for? A cool $5 billion.

Timothy O'Brien, a business reporter on the New York Times who has followed Trump's career for more than a decade, alleges in TrumpNation: The Art of Being the Donald that the property tycoon routinely exaggerates his wealth.

Trump has taken up the sword of truth, declaring in a statement that he believes "it is important to expose irresponsible, malicious and false reporting", and adding that he had given the author comprehensive financial information before the book was published - information which Forbes magazine had used to estimate Trump's net worth as "at least $2.7 billion".

Warner Books are standing by their man, calling him "one of the nation's leading business investigative journalists", putting "every confidence" in him, and proclaiming that they "firmly believe in Tim's research for the book".

Trump is the latest in a long line of celebrities who have turned to the courts as a way of marking their displeasure about the publication of a biography, including Clint Eastwood, Neil Young and JD Salinger.

So perhaps Spurling's first triumph was her choice of subject. Dead men, even the perenially impecunious Matisse, don't sue.