Normally you have to pay to enter writing competitions, but one of the largest is free to enter: the BBC National Short Story Award (top prize £15,000). Entries are now open for the 2013 competition.
Is there a catch? Yes. You have to have been 'traditionally published'. So it isn't a competition to find the best new writing, it is a competition to find the best writing by people who have already had some success. It is interesting that it excludes the vast majority of writers by inserting a rather old-fashioned clause in the terms. So the writers who have become millionaires from their e-books can't enter; nor can writers who have to self-publish literary fiction that does not have a large enough commercial market to tempt traditional publishers. The restriction is doubly strange seeing as how both the BBC and the Booktrust are publicly funded (I think the Booktrust gets about £6 million a year), yet they are using money for these vast prizes with caveats which serve only to legitimise and maintain the status quo.
I'm not ranting because I can't enter (luckily I was published in Sarasvati, a magazine that has been around for over twelve months and has an ISSN, so I am legit!) but because I think it is a shame that so many excellent authors are prevented from entering a competition that their taxes are going towards funding.