Copyright is an intellectual property right that exists to protect the rights of the person who has created something and covers many different things. The current act is the Copyright, Designs and Patents Act 1988. All of the items that I create are covered by this law.
Infringement of Copyright can include but it is not limited to : Copying, renting, reselling, sharing, adapting, distribution either freely or for financial gain.
I would like to point out that I encourage the people that buy my products to sell their finished cards and I place no limits on this. There are other craft suppliers that put limits on this but there is a clause about 'Fair Usage' in Copyright law that allows you to sell your finished items, it comes under the name of 'incidental inclusion' this would only cover a finished article and not the designs themselves.
If in doubt please contact me direct or visit this website