Generally, if you've registered the name in good faith, it's not a name belonging to an internationally known company, and you can show that you have a legitimate reason to use that name, then you are likely to be able to keep that name.

That may not be the case if it can be shown that you purchased the name for the express purpose of re-selling it to a company with a legitimate claim to the name.

Please see the Dispute Resolution Policy for details:

www.nominet.org.uk/disputes
www.icann.org/udrp/udrp.htm