With the imminent release of the 7th installment of Star Wars this is an interesting blog from the IPO outlining the about the intellectual property rights behind the films and how these are exploited commercially.

When the original film was distributed created George Lucas famously kept the merchandising rights and it is the intellectual property rights (including the 105 UK registered trade marks) that form the basis for protecting and exploiting those merchandising rights.

That said, Lucasfilm hasn't always got things right, including the dispute with Andrew Ainsworth (who designed the original Storm Trooper Helmet). Following a protracted legal case in 2011 the Supreme Court confirmed that Mr Ainsworth was free to sell copies of the Star Wars Helmet in the UK.