Ryan Gilbey on film

On Monday, Brenda Blethyn (below right) was named Best Actress at the Cannes Film Festival for her performance in Mike Leigh's new film, Secrets and Lies. It's a victory that makes you bunch up inside, or clap your hands. That's because Blethyn has created a character which cannot be contained by the screen. So you feel that the win is as much Cynthia's as it is Blethyn's - you imagine how this jittery, loving but largely unloved factory worker and put-upon mother would react to the approbation. That's the giddy thrill of Blethyn's performance. It's utterly real, intangibly so. You could list the cumulative details: the way she wrings her hands, admires her own legs, peers out nervously from her front door as though she's expecting a clip round the ear. But the essence is amorphous. She's magnetic.

Blethyn fills every corner of Cynthia's existence, and that in turn spills over into your life. She's the sort of character that you think about in the afternoon, as though she were a friend that you'd just shared your lunch-break with. The whole film has this diffusive quality - relinquishing it when the 141 minutes is up is tough. But Cynthia in particular nestles in the heart. David Thomson should fashion a chapter out of her in his book Suspects, which imagines the extra-curricular lives of various movie characters. I keep waiting to bump into her on the Tube.