It is possible to apply to have a patent revoked after its registration.
The grounds on which a patent may be revoked are set out in Section 72 of the Patents Act 1977 and the corresponding Article of the EPC.
These state that a patent may be revoked if
i) the invention is not a patentable invention
ii) the patent was granted to a person who was not entitled to that patent
iii) the specification of the patent does not disclose the invention clearly enough and completely enough for it to be performed by a person skilled in the art
iv) the material in the patent extends beyond the material in the application as filed.
It is set in law that any person can apply to have a patent revoked regardless of whether or not they hold an interest in that patent being revoked.
The availability of patent revocation action means that it is vital that before a patent application is filed it is important to have a thorough search conducted and that the patent is drafted by professional.