A patent can be challenged. Every Patent application will be assessed by a skilled Patent Examiner to ensure that it complies with the relevant statutory provisions governing Patents. However it is not possible for the Examiner to know every possible piece of prior art that may exist and as a result anyone is permitted to apply to the Patent County Court or High Court or to the Intellectual Property Office to have a Patent revoked.
If successful the Patent application will be removed in whole or in part. Similarly even before the Patent is granted, written observations may be made by a third party once the application has been published should that third party wish to defeat your Patent.
It is important to note that registration of a Patent does not mean that the registrant is not infringing another’s Patent and therefore due diligence is essential.
Existing rights will usually be identified in a Patent search however caution should always be taken. In fact even if you are not considering securing a Patent you should seek legal advice to ensure that you are not infringing another’s intellectual property. A standard Patent search will assist with this.