The discovery of Cannes (so far)?  Katie Jarvis.

Andrea Arnold, director of the Cannes competition entry “Fish Tank,” at the festival today. Photo by Eugene Hernandez

Andrea Arnold made her new film in an intimate 4 x 3 format to literally center the image on her young lead actor at all times, frequently following the character around in that same way that The Dardenne Brothers or Gus Van Sant have traced their actors on camera. Shot in sequence and in the hand-held tradition of other British realism, “Fish Tank” evokes the documentary filmmaking tradition that Andrea Arnold brings to her work from her early days in television. It’s her second time with a feature film in Cannes after 2006’s Prix du Jury prize-winner “Red Road.” Before making the leap to narrative features, Arnold gained international attention for her acclaimed short films, “Milk,” “Dog,” and “Wasp.”

The lives of Arnold’s characters in “Fish Tank” often seem so bleak and they seem so trapped. Then, however, a song comes on and they escape by dancing. Yet, not in that stylized “Billy Elliot” fashion, with a loud, driving soundtrack. In this case, a music video is on the TV or a tune played on little speakers connected to a portable Discman, And the characters escape.

Personal dramas lead to occasionally dramatic twists and turns for this trio of females in “Fish Tank,” culminating in a tender, unexpected moment of release near the end of the film, just as lives seem poised to change.

In her own hotel room here in Cannes yesterday, “Fish Tank” director Andrea Arnold admitted that she was feeling quite anxious ahead of today’s world premiere. “I put on my iPod and had a good old dance around the room,” she admitted, “I think that dance is a great way for relieving tension.”