A patent can be revoked if it is obvious. Section 3 of the Patents Act 1977 provides that an invention shall be taken to involve an inventive step if it is not obvious to a person skilled in the art.
Section 14(3) of the Patents Act provides:
“The specification of an application shall disclose the invention in a manner which is clear enough and complete enough for the invention to be performed by a person skilled in the art”.
Section 72(1) of the Patents Act provides for the revocation of a patent on grounds which include:
“(c) 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”.
Whether or nor a patent was obvious was set out in Lord Diplock’s Judgement of Catnic Components Ltd v Hill & Smith Ltd  RPC 183
“persons with practical knowledge and experience of the kind of work in which the invention was intended to be used”.