There are many shields available to deflect the sward of patent infringement. That is, private, prior and experimental use of a patent.
Private use – where the defendant is using the patent for non-commercial purposes, within SFK -v- Evans and section 60(5)(a) of the Patents Act 1977 (“PA”).
Experimental use – by section 60(5)(b) one may use a patent for experimental use. If using a patent for experimental use one should be sure to have the motive of experimentation and not for example to gather information from a rival. See for example Monsanto Co -v- Stauffer Chemical Co and SFK -v- Evans.
Prior use – whilst a shield can also act as a sward directly against the validity of the patent at issue, which could result in the patent being rendered invalid. The primary effect of the prior use doctrine is to deflect an action for patent infringement where it can be shown that the defendant used the patent prior to its priority date and after where such use is substantially similar.