From Dave at Shoreline Scripts:

Shoreline Scripts is the only active standalone screenwriting competition in the UK. We wanted to create not only a competition with awards, but a platform to help get great scripts from around the world into the hands of the producers and companies that have the means to get them made. We have the best judges of any screenwriting competition out there. They’ve been Oscar, Cannes Palme d’Or and BAFTA nominated. You can read about our prizes here.