What unfolds is an urgent, quietly gripping thriller following a prostitute and her 14-year-old charge on the run from a paedophile crimeboss and the apparently inescapable reach of his organisation. Battered and bruised to a painful extreme not seen witnessed on screen since Gary Oldman's Nil By Mouth, Kelly (Lorraine Stanley) and Joanne (Georgia Groome) embark upon the journey of the title, and as the story of how they came to be beaten up so unfolds in flashback, the net surrounding them starts to close in. Williams' own closeness to his performers yields a terrifically vivid turn from Johnny Harris as Kelly's pimp and middleman, just smart enough to figure out the terrible position he's in; it's a turn summarised by a shattering moue of of the actor's lips as he tempts Joanne with the offer "go play with him, and I'll give you £100", choosing his words as though to suggest the business he's caught up in was just child's play, rather than kiddy-fiddling.
Harris's pimp is typical of the forceful characterisation running throughout; while there's some sparse humour here, and a bleary, early-hours-of-the-morning poetry, too, Kelly and Joanne are very definitely at the mercy of the cold hearts of bad men. These low-lifes aren't joky rogues, or stand-ins for a director who wants us to think he's far tougher than he actually is: Williams remains resolutely unimpressed by his antagonists' violence, and stays on the right side of those doorways separating us from a bloodbath. He knows the film already has enough of a sense of horror in its scenario to power itself along, and to garner those sympathies not already engaged by Stanley and Groome's fine, committed performances. This is a very impressive debut.
London to Brighton screens on BBC2 tomorrow at midnight.