The film has had a limited release in the UK and is still playing in some theatres. It opens in the US on April 16th, also at limited theatres but gradually widening to include more.
The film come out in the UK on June 28th on DVD and Blu-Ray.
Embedded below are the first five minutes of the film which give a really good taste of the film and represent the tone a lot more accurately than either the UK or US trailers.