For Latham is at war with the Tate because of the withholding of a key piece: as he sees it, this is an act of at best cowardice, at worst censorship. He has scored a small victory in getting the gallery to agree to a notice saying the piece has been withheld "without the consent" of the artist. Now, the Tate has agreed to host a public debate on 8 November on the issues surrounding its decision.
"Somebody called it a failure of nerve," Latham tells me, in the only interview he has given on the matter. "I think the Tate management feels itself to be responsible to the public rather than to the artists they exhibit, which is a terrible indictment.
"To say that we can't have this in here when they know it's right in the middle of the art track is a failure of common sense. It's an interrupted discourse, and, therefore, it's a form of assault for purposes that are nothing to do with the art."
The piece in question is God is Great, made in 1991 and last exhibited in March this year at the Lisson Gallery in London. God is Great consists of a 6ft-high piece of plate glass with the Bible, Talmud and Koran extruding through it. The problem with it, the Tate Britain director Stephen Deuchar told me, is that gallery staff felt that they were in danger of being attacked by religious extremists in the post-7 July climate. He hadn't actually consulted terrorism experts or even the police, but had talked to Muslim scholars who felt that the piece would be seen as an abuse of the sacred Islamic text.
"It's an arbitrary decision made in ignorance of the considerations that went towards the presentation of the piece," Latham says. "The literal meaning is that all inspirational belief systems derive from a single source, represented by the glass, from which all utterances are drawn on a vast number of now numerate levels."
Latham's work is admired the world over. He has been called a visionary on equal terms with William Blake, and, even at 84, is still habitually labelled an enfant terrible. Books are the cursor in Latham's work. At the front of his home in Peckham, south-east London, two giant books protrude through what was once a shop window, their pages interleaved in bibliographical congress. He made news almost 40 years ago when teaching at St Martin's School of Art. He borrowed from the library a copy of Clement Greenberg's seminal Art and Culture, in which the critic and godfather of American Expressionist painting expounded his theories of modernism, which Latham regarded as a tendentious carving up of artistic thinking. Latham and his students dismembered the book and chewed every page, before Latham arranged the regurgitated remains in a travelling-case. Now entitled Still and Chew/Art and Culture, 1966-67, it's in New York's Museum of Modern Art. But the St Martin's authorities did not see its artistic merit in 1967, and Latham was duly dismissed - when he failed to return the book to the library.
Earlier in the Sixties, Latham made the news with his Skoob Towers, piles of books that he solemnly built beside the Hayward Gallery on the South Bank and then set fire to. "Those things were never intended to be provocative, any more than God is Great is," Latham says. "They were a natural progression of what I was doing at the time."
And time has been Latham's obsession for more than half of his life, and the reason why there were scientists at his private view as well as artists. (Stephen Hawking was only prevented from attending by his book tour.) Like Hawking, Latham is driven by the concept of different time dimensions. Scientists, he says, believe in two levels of time, a cosmological one and the linear, everyday sort. "The problem is that physicists can't visualise it, and they've got into an awful tangle. I say that all time is event-based, like a spray of paint: the spots can be seen as a happening issuing from a single event, the pressing of the spray's trigger.
"What people don't realise is that physics has collapsed, and the authority for that comes from Hawking. Ten years ago, he said it might take to the end of the century to solve it, now he says it might take 100 years. He acknowledges it's an insoluble problem, but the trouble with Hawking is that he can only think in the orthodox."
Which is rather Latham's problem with the Tate. In spite of its willingness to acknowledge artists' achievement, when confronted by apparently unconnected events they can't break free of the bounds of orthodoxy. There were to have been what he sees as three key pieces in the exhibition: Full Stop, of 1961, a huge, black painted circle that represents an event and its unknowable consequences; Time Base Roller, of 1972, an attempt to visualise the mathematical calculations of his "Flat Time" theory; and God is Great, embodying the notion of faith as an event. The progression, Latham says, has been broken by the withdrawal of the last piece. "It's in the Tate's collection, a present from me, and I've asked for it back, though not directly. It's complicated."
The complication is the Artist Placement Group, set up by Latham and his wife, the artist Barbara Steveni, in the Sixties to put artists into government departments and companies so that they might add their unorthodox thinking to the process of, say, town planning. An APG archive, kept by Latham and Steveni, was acquired by the Tate earlier this year in a £100,000 arrangement involving these three major pieces, whose status as gifts or purchases is not clear. "That's why I haven't asked for it back point-blank."
Meanwhile, the controversy continues: "I was berated in the street yesterday by a Jewish member of the community who thought I was criticising Jewish theology, but it's not theological or political in any way," Latham says. "I told him that it's simply that each of these books is in the format of linear time, but they are not complete, each is as incomplete as the others, and I thought that that was fair comment.
"What I want to say is that this is how history looks to me. I'm saying that this is historically what happens, whether I like it or not."
John Latham in Focus, Tate Britain, Millbank, London SW1 (020-7887 8000), to 28 February 2006Reuse content