So what exactly does a "curator of interpretation" do? As interest in modern art has taken off in the past 10 years, the Tate has evolved new strategies to explain and enlighten, and while his job's title may seem intimidating, it exists, says Wilson, to ensure that exhibitions are free of art-history jargon and assumptions. "I am the defender of the general public," he says.
Wilson was inspired to study art at the Courtauld Institute because Anita Brookner, the future novelist, gave "brilliant" lectures in French art history during his original French degree. He has worked at the Tate for 32 years, first as an official lecturer, then in education, and as "curator of interpretation" since 1992.
He is the gallery's chief writer and editor of text - the captions on the wall, the brochures that accompany the exhibitions, and the longer catalogues. He gives talks to the employees of its corporate sponsors, briefs the media, and is responsible for 40 volunteers who do tours.
Yet he was greeted with unhappy grumblings throughout the curatorial community when he first dared to suggest that they should help the public to understand the art in their charge.
As long ago as 1977 Wilson delivered a satirical paper at an art historians' conference entitled Curators' Cultural Conditioning and the Myth of the Self-Evident Artwork. This was in the days when curators tried to cram as many works into galleries as possible, he says. They saw captions as an unnecessary waste of wall space and viewed the collection as a reference book for academics.
Even 10 years later he had made little headway in what he describes as "a great battle - the issue of text in galleries". But when Nicholas Serota took over as the Tate's director in 1988, he got his chance. Sir Nicholas ordered a complete rehang of the galleries, instigating a policy of rotating the collection so that more of the works in storage - 85 per cent at any one time - could be seen. Alongside that was developed the idea of interpretation. "Interpretation very much doesn't mean foisting a specific interpretation on the general public," Wilson says. "What we try to do is provide certain facts about the work that we hope will give people clues or draw people into looking at the work more deeply."
It is an interesting titbit of human interest, he says, if you know that Picasso's Nude Woman in a Red Armchair is his lover of the time, Marie- Therese Walter.
"Generally speaking, the Tate's approach to interpretation is to establish the intentions of the artist," Mr Wilson says. "In the art historical world, that is deemed to be fantastically old-fashioned or, indeed, plain wrong. Academic art historians think it's irrelevant what the artist intended."
The Snail by Matisse, for example, purchased by donors in the late 1950s after the Government refused the Tate the money to obtain what it considered a bafflingly abstract work, is now regularly used in education work with children. They are told the story of how Matisse started by watching a snail in his hand and drawing it, and how the bright colours reflect those of the Mediterranean where Matisse worked.
These efforts to educate visitors have paid off, Wilson thinks. Attendances have risen from 1.2 million in 1989 to 2.1 million last year and the recent Jackson Pollock show proved one of the gallery's 10 most successful exhibitions. Sir Nicholas Serota certainly believes Wilson's work has been crucial. "It creates a bridge between the curatorial expertise and the general public."
No other gallery has anyone with the same title and role as Simon Wilson's, yet it has proved so successful that the new Tate at Bankside next year will have a "head of interpretation and education", not just "education".
"It's one of the things that makes the Tate a more approachable museum of modern and contemporary art than many others," Sir Nicholas says. "People find things that intrigue or annoy them, but they get some form of explanation and begin to get a purchase on what the artist is doing. We don't make the assumption that everyone who comes in is a convert."