"We lived in the same neighbourhood and that fall we became friends. He was a class ahead of me and was by far the bolder of the two of us. He was always the one to take the first step and I was the one who followed. He always chose a higher point to jump from. He had sex be fore I did, and when I was thinking of buying a moped he had already sold his.

He still lives in the town where we grew up and now he has a wife, two sons, a home in a terraced house and a steady job. The security of his life appalls and attracts me at the same time.

I have spied on him and his family for a year now and secretly photographed them.... they know that I'm there but they don 't know when."

Somewhere in a small city in the west of Sweden, near Gothenberg, a man goes about his life -he wakes up, takes the children to school, goes to work, comes back, speaks to his wife. At the weekends he breakfasts on the balcony or barbecues for friends. He appears absorbed in these daily rituals, rarely smiling. It is a perfectly uneventful family life - except for the event of it being photographed.

For over a year, Ulf Lundin spies on this man and his family, snatching shots through his windows, from behind the bushes in his garden, or hidden in his neighbour's house. Lundin even follows the man on his summer holiday.

This man - who remains anonymous - is Lundin's erstwhile best friend, the boy at school whom he followed and heroised. Years later, temporarily himself impecunious, single, living in a bedsit, Lundin wonders about the man whose life has become a mirror reflection of his own, the man who seemingly has everything. The two enter into a strangely consensual game. Lundin has permission to spy as long as he is never seen.

Despite its exhaustive chronicle - over a hundred rolls of film exist - and despite its obsessive voyeurism, the serires is not a documentary work. It is less a portrait of the family than a self-portrait of the photographer. The work hints at one of the strange truths of the medium: that the photographer, although supposedly observing subjects in the world, is more often driven by the need to find his or her own image refracted back through the prism of the lens. For none are quite as self-absorbed as those who devote their time to surveilling others.

Ulf Lundin was born in 1965 and currently lives and works in Stockholm. He has been the subject of solo exhibitions at Galeri Magnus Karlsson in Stockholm (1998) and Galleri Hippolyte in Helsinki (1997). This is his first exhibition in the United Kingdom.