Patent infringement is a tort and actionable by the patentee or an exclusive licensee. The definition of infringement can be found under section 60, Patents Act 1977.
A person infringes a patent for an invention if, but only if, while the patent is in force, he does any of the following acts in the United Kingdom in relation to the invention without the consent of the proprietor of the patent:
(1) where the invention is a product, he makes, disposes of, offers to dispose of, uses or imports the product or keeps it whether for disposal or otherwise
(2) where the invention is a process, he uses the process or he offers it for use in the United Kingdom when he knows, or it is obvious to a reasonable person in the circumstances, that its use there without the consent of the proprietor would be an infringement of the patent
(3) where the invention is a process, he disposes of, offers to dispose of, uses or imports any product obtained directly by means of that process or keeps any such product whether for disposal or otherwise.
In most cases, it is necessary to show that the invention has in some respect been taken. The invention is defined under section 125(1) of the Patents Act 1977 as that specified in a claim of the specification of the application or patent, or as interpreted by the description and any drawings contained in that specification.
In some cases it also involves construing the specification and claims so as to assess whether the product or process falls within the claims of the patent. The process of determining infringement is not easy and is reserved for lawyer and attorneys with relevant backgroungs in the field of the patent.