Oscar-nominated in 2007 for 'Days of Glory', director Rachid Bouchareb once again explores culture clashes and the bonds of friendship with 'London River'. In 'Days of Glory' he told us the story of the North African men who fought for France during World War II. Here we're brought into the lives of a mother and father who meet under the most harrowing of circumstances.

When she watches the news flashes about the terrorist attacks on London on 7 July 2005, Guernsey farmer Elisabeth (Blethyn) immediately telephones her daughter, Jane, who is studying in the city. She gets Jane's message minder, and 24 hours later still hasn't received a call back. With her mind racing, Elisabeth decides to leave her island home and travel to Jane's flat.

Also arriving in the same area of London is Ousmane (Kouyaté), an African forestry worker who lives in France and is trying to reconnect with his now adult son, Ali. Ali cannot be found either, and as Ousmane and Elisabeth scour the city for information on their children they meet - only to discover they have more in common than they think.

This small but very powerful film features excellent performances from Blethyn and Kouyaté and is made all the more poignant because the late Malian actor was seriously ill during the production. Through the characters of Elisabeth and Ousmane, Bouchareb examines fear, distrust and loneliness and brings every family's worst nightmare to life. The tension is at times unbearable and the dread gnawing at each parent also has its way with the viewer.

Both Elisabeth and Ousmane are adrift in a strange environment, but he is far more willing to see the good in people than the very sheltered farmer. When Ousmane contacts Elisabeth because he thinks he might be able to help with the search for her daughter, she thinks he has something to do with her disappearance. To watch Blethyn's character grow in one way and wilt in another feels completely true to life, while the quiet dignity and stoicism of Kouyaté's Ousmane is unforgettable.

Bouchareb shows that even in a city as frenetic (and at this time traumatised) as London the kindness of strangers is around every corner and that we have far more holding us together than keeping us apart. That's a lesson that can't be learned often enough.

Harry Guerin