There are two systems that can grant patents covering Britain: the national system and the European system. Each system can be applied under the international system.
Patent applications under the national system have been filed with the British Intellectual Property Office (IPO). Any natural person or legal person can apply in Britain, as long as they are inventors or have the right to own property.
Applications submitted under the European system have been filed with the European Patent Office (EPO). It makes it possible to apply, sue and grant patents centrally. If you want to protect in many countries belonging to the European Patent Convention (EPC), this is an easier and cheaper option than submitting a single application.