542. Claimants in proceedings for infringement.

The right to bring a claim for infringement1 belongs to the proprietor of the patent2, to his exclusive licensees3 and, in certain circumstances4, to holders of compulsory licences5 and licences of right6. The claimant probably need not first secure entry of his title on the register of patents7, but failure to do so may limit his right to damages8. When a licensee sues alone, the proprietor must be made a defendant, although he is not liable for costs unless he acknowledges service of the claim form and takes part in the proceedings9. Where the proprietor sues, it is usual