what are the ramifications for a small USA based record label to release an album without permission that is copyrighted with a small UK based record

The consequences wouldn't be any different from releasing music without permission that's copyrighted in the U.S., because of international copyright "conventions," treaties that promise mutual enforcement of copyrights among all the nations that sign the treaty.  The damages for copyright infringment start with any and all profit you make from the unauthorized publication, and you'll be stuck at least with your own legal fees.  This can't be worth the risk;  buy the rights!