Dog Day Afternoon meets modern-day terrorism in Red Mercury. Shot in the Old Street area of the City of London, Red Mercury is one of those political thrillers that cry out for a classic Hollywood trailer - the ones in which newspapers spun into focus and a giant banner exclaimed 'Ripped From Today's Headlines!'. Except that, fortunately, the headlines that would have accompanied the story of Red Mercury have not yet appeared in any newspaper.

Three young members of a terrorist cell - Asif (Navin Chowdhry), Shahid (San Shella) and Mushtaq (Alex Caan) - are warned of an impending police raid and flee their flat with the makings of a bomb. When they discover that their car has been clamped, they take refuge in a nearby restaurant, and the establishment's well-to-do diners become hostages.

Before long, a sophisticated police and security services operation has been assembled outside, taking on added urgency when its leader, Sofia Warburton (Juliet Stevenson), discovers that the three young men are in possession of red mercury, a potential ingredient for what the London security services fear most: a 'dirty' bomb, capable of causing far greater death and destruction than an ordinary explosive device.

Struggling to find a way of resolving the siege, Warburton and her counterpart from the Metropolitan Police (played by Oscar nominee Pete Postlethwaite, probably best known to younger audiences as Kobayashi in The Usual Suspects), delve into the background of the three terrorists. One of them, Shahid, comes from an impoverished, single-parent background and was a bad boy until he found religion. The second, Asif, is a Cambridge graduate with a double first who was a successful taster in his father's wine warehouse before converting to Islam. The third, Mushtaq, the leader of the group, has a Ph.D in physics. All three are typical in different ways of the kind of lives lived by second-generation British Asians. But they have all clearly chosen to reject those lives, and Farruk Dhondy's screenplay sets out to discover why.

Like Dog Day Afternoon, Red Mercury explores the shifting dynamics of the relationship between the three young Muslims, as well as those between the restaurant customers - who include Stockard Channing and Ron Silver from hit TV series The West Wing - and between the terrorists and the diners.

The film follows the relationships that form between the three boys and their hostages, as well the intelligence operation taking place outside. Things come to a head when Sofia, trying to communicate with the boys and finally discovers that they might have some kind of dirty bomb in there. Should the special forces be sent in to end the siege or continue to negotiate.