The Finborough is a Fringe theatre in a class of its own: last year's programme was so good that it was worth moving to West Brompton for – if only you could afford to. Its first new writing premiere of the year is a bruising lyrical short about teenagers in London whose quality and impact suggests that 2012 in London's only wine bar theatre, will be as impressive as it was in 2011.
'Fog' is unique as a piece of new writing: I can't remember the last time a sixtysomething founder member of a lesbian feminist theatre group teamed up with a twentysomething actor to write a play, but Tash Fairbanks and Toby Wharton's benefits richly from the verve and faux-yardie argot of youth and the poignant wisdom of experience.
Its themes and narrative arc aren't quite so unusual. Pumping, alienated urban yoof portraits are often the first base for new writing. But 'Fog' has a tenderness and subtlety – drawn out beautifully in Che Walker's rhythmic, observant production – which deepens its impact.
Wharton plays the mixed-up kid lead, Fog, in a performance that fills all the gaps in the part he co-wrote. His relationship with his absentee soldier father Cannon is emotional dynamite. Cannon (the excellent Victor Gardener) has returned from the wars to a dingy council flat, shit £12k per annum job prospects, and the hopeless aim of parenting the kids he put into care when their mother died.
The generational counterpoint is acute: Cannon is purposeful, macho and frustrated by a changed world; his son is an aimless styler who raps about violence and deals weed yet, despite his harrowing years in care and downward trajectory, has a capacity for empathy that his father lacks.
The climactic scene in which Cannon spars with the teenage Fog, who is too old to learn and collapses, clinging to his disgusted father like a baby, is aching and explosive.
The play sketches another counterpoint between Fog and his uni-bound best friend Michael (Benjamin Cawley). Michael has, crucially, a home and a sister who is annoying but able to take care of him. The superb actors make this more schematic relationship both nuanced and moving.
Opening in a week when housing benefit has been capped – a policy which will hit London's inner city where it hurts – 'Fog' is not only a subtle study of lives adrift: it is also a powerful warning about what happens to kids and parents when they don't have a home to call their own.