erastes

Contains this little clause in the very small print.

"Where you submit your entry to this site (including without limitation any text, graphics, photos, video or audio) by such submission you grant UKTV and Harper Collins Publishers Limited each a perpetual, irrevocable, royalty-free, non-exclusive, worldwide, sub-licensable right and license to use, reproduce and publish, distribute and make available to the public your entry in any media, now known or later developed, for the full term of any rights that may exist in such content.
If you do not wish to grant such rights to UKTV and HarperCollins, you should not submit your content to the site."

So, basically, even if you don't win, you grant them rights to use your submission exclusively for ever and never to pay you a penny.

Take their own advice and Do Not Enter.