Somone patented the idea I had a few years ago. Although I have never seen the product in the shops, does a patent ever expire ?
A patent has two aspects – one as a published document (like a magazine article or newspaper), and secondly as a legal document which will protect your market. If you are sure your idea has already been done (i.e. you’ve seen it published as a patent specification and it is exactly your idea), then it will always be in the public domain, and you cannot patent it again. As a legal document, you can check to see if the patent is in force here, or let me know what the publication number is and I’ll check for you. If it has lapsed, then you cannot infringe it and could market and sell your own device – but you wouldn’t be able to protect your market (because you can`t patent the same thing again). This would mean that your market would be open to competition from others.
