This chapter deals with patent infringement and the scope of protection that the law provides to patent owners. It discusses three criteria that are used to determine whether a patent has been infringed: the types of activity that constitute an infringement; whether the activity in question falls within the scope of the patent monopoly; and whether the defendant is able to invoke any of the defences that are available to them. The chapter discusses in detail the right to make a product (and the relationship with repair), the concept of a ‘direct’ product from a patented process, and infringement of new medical use patents, as well as ‘indirect’ infringement by supplying means to put an invention into effect. It then considers the scope of protection, closely examining the evolution in the United Kingdom of the interpretation of claims and the recognition of a doctrine of equivalents extending the scope of protection beyond the terms of the claims. The chapter also examines the defences of private and non-commercial use, experimental use, and ‘farmers’ privileges’.