FOUR months ago the shock of the 2005 Turner Prize was that a painter who creates landscapes and still lifes with old-fashioned brushes was among four shortlisted artists.

Yesterday, the Tate ensured that Gillian Carnegie’s art had the required dose of controversy to be worthy of Britain’s most provocative art award when it unveiled her latest work — depictions of her own bottom.

The gallery hailed her “bum paintings”, which hang alongside her landscapes, as experiments in composition, light, colour and technique. Carnegie, 34, paints her bottom from photographs that she takes herself. Her art “capitalises on the tension between subject and medium”, curators wrote in an exhibition wall panel intended to explain the work.

Each of the shortlisted artists has created new artworks for the competition, which are exhibited at Tate Britain from today, before the winner is announced on December 5.

A crumbling boat shed, which the Glaswegian artist Simon Starling brought over from the Rhine in Germany, is among other contenders.

Starling dismantled the boat shed before turning it into a boat and then back again into a shed. Tate curators saw it as a “poetic” work, “a buttress against the pressures of modernity, mass production and global capitalism”.

Darren Almond, a Londoner who previously transported a bus stop from outside the Auschwitz Museum in Poland, has created a four-screen video installation of his grandmother reminiscing about her honeymoon in Blackpool. The Tate said that it was “a space for anyone to dip into their own memories”.

It is not often that visitors can walk on a piece of art, but the Glasgow artist Jim Lambie’s floor installation means that they have to do just that.

His piece, The Kinks, includes giant bird figurines placed on a psychedelic floor of black, white and silver tape strips. He found the garishly-painted bird ornaments in a junk shop and commissioned a ceramicist to turn them into massive examples.

Lizzy Carey-Thomas, curator of the Turner Prize exhibition, described this year’s artworks as clever. Asked to explain, she said: “What they’re doing is complex . . . and unique.”

On why Carnegie paints that particular part of her anatomy, Ms Carey-Thomas said: “With her bum paintings, she is showing a level of detachment that she shows with anything else. It’s a wonderful site for experimenting with her palette and lighting effects, drawing out the erotic connotations sometimes, or diffusing them. She is aware of the history of the female nude. It’s a reclaiming of that territory in some ways — subverting the male gaze by painting her own bum.”

David Lee, editor of The Jackdaw, said that the Turner Prize had started giving “undue prominence to mediocrity”.

He said: “The prize’s real problem is that it’s got to the stage where the people who win it are not really worthy of it. It’s not first-division artists. We’re dealing with seconddivision artists here. If you went round any number of galleries in Shoreditch and Hoxton, you would see works that are similar.” He dismissed Almond’s video piece, saying that “you wait a long time for almost nothing to happen”. Lambie’s birds were “superlative kitsch”, while Carnegie’s flower paintings would not get a second glance if they were anywhere other than the Tate.

The Turner Prize is no stranger to controversy. Previous winners include Damien Hirst, best known for his works using preserved animals, and Martin Creed, who arranged for a light to flicker on and off in a bare room. Each year, the exhibition draws up to 100,000 visitors. This time, it is sponsored by Gordon’s gin.