This Practice Note deals with court powers to take action against internet service providers (ISPs) in relation to infringement of intellectual property (IP) rights. The infringement is usually in the form of peer-to-peer copying of films or music files or via websites which facilitate access to streams of television broadcasts of sporting events; where that is found the courts may make an order under section 97A of the Copyright, Designs and Patents Act 1988 to block access to the infringing website, from the UK. It covers website blocking based on copyright infringement and trade mark infringement including an analysis of the Cartier case, live and dynamic blocking orders, costs of applications, forms of order and what is next on the horizon for blocking orders.