An International Patent application may be filed in English at the UK or European Patent Office and may designate any of over one hundred countries or regions (including the UK). A separate designation fee must be paid for each country or region designated at the date of filing the application (although there is no fee for the sixth and each subsequent designated country or region).
Shortly after filing the International Patent application, a European Patent Office examiner is appointed to conduct a search through previously published patent specifications and a limited range of other literature to identify published documents which may be relevant to the patentability of the invention. The International Search Report listing these documents is sent to the applicant (together with a copy of the documents). The Search Report will include a written opinion, which states whether the invention appears new, involves an inventive step and is industrially applicable. The written opinion will also detail any formal deficiencies of the application.
The Search Report and written opinion may be used when deciding whether to continue with the application or abandoning the application. The applicant may file informal comments on the written opinion and such comments may rebut the opinion and provide arguments in favour of the invention. Also, the applicant may file amendments to the claims of the application in light of the Search report and written opinion. The International Patent application is published and by a specified date the applicant must decide whether or not to request International Examination and pay the International Examination fee.
The publication will include any amendments to the application or comments filed by the applicant. The applicant may request that the application is subject to an International Preliminary Examination. If International Examination is requested, an International examiner is appointed at the European Patent Office and issues a non-binding opinion on the patentability of the invention. The Office will initially send the applicant a first written opinion (similar to the opinion issued with the Search report) indicating any shortcomings of the invention and the application. The applicant has the opportunity to file comments and amendments in response the first written opinion. The Office will then issue the formal International Preliminary Examination report. By a specified date which varies from country to country, but usually 30/31 months from the priority date, the International Patent application must be split into separate Patent applications in each country or region in which Patent protection is desired.
Various formalities must be fulfilled in each country or region and may include the requirement for a local language translation to be filed at the local Patent Office. Having split the application into separate Patent applications in the countries or regions of interest, the International Patent application ceases to exist. The separate or regional Patent applications continue in the manner described in the other briefing papers for national or European Patent applications.
The most up-to-date list can be found on the World Intellectual Property Organisation (WIPO) website. All major industrialised countries are members. The filing of an international patent application very effectively buys time and the option of continuing patent prosecution in a large number of countries. This enables the high cost of international country filing to be delayed, e.g., until the commercial viability of the product has been tested in the marketplace.