A 'divisional' application under UK patent law is made under the provisions of section 15(9). An important point to note is that nowhere in the Act or Rules is the word 'divisional' used. The term is commonly used merely as a convenient shorthand to describe such applications.
Time Limits
Divisional applications may be filed within the period ending three months before the compliance date (Rule 30) of the earlier (parent) application, provided the parent application is still pending (Rule 19). The compliance period is normally within 4 years and 6 months from the first priority or filing date, although this is extended if the first examination report (under section 18(3)) is issued within the last 12 months (Rule 30(2)(b)). If the first examination report is made under section 18(4), i.e. the application is in order for grant without need for amendments, the applicant has two months (under Rule 19(3)) within which to file a divisional application. If an examination report is issued under section 18(4) after the applicant has already responded to a report under section 18(3), there is no requirement for the examiner to give the applicant any further opportunity to file a divisional application, and the application may proceed to grant immediately.
"Foreshadowed" Applications
In practice, it is prudent to file any divisional application before responding to a report under section 18(3). Examiners may take into account clear notices in an applicant's letter indicating that a divisional application is contemplated, giving the applicant a limited further period after issuing a section 18(4) report, but this is at the examiner's discretion. The IPO has issued a practice notice on the procedure to be taken by examiners when dealing with applications where a divisional has been 'foreshadowed', following the case of Howmet Research Corporation [2006] EWHC 725 (Pat). Briefly, examiners are to give the applicant two weeks' notice if the most recent letter foreshadows a divisional application, to give the applicant an opportunity to file an application before the application is granted.
Overlapping Scope
The dependent claims in a divisional application can often end up having a scope that overlaps with claims in the parent or another divisional. The examiner could refuse such claims under section 18 (5) but there seems to be no real justification to do so as the two applications will not cover the same invention. For a typically robust discussion of section 18(5) by Jacob J see the 14 February 2003 judgment on the amendment in Synthon BV and SmithKline Beecham Plc (2003) IPD 26032.
Added Subject Matter
When preparing a divisional application, care should be taken to avoid inadvertently adding subject matter. In the UK section 76 makes this a correctable offence while the application is still pending. The position is the same at the EPO, after the Enlarged Board of Appeal decision in combined cases G 1/05, G 1/06 and G 3/06 (see IPKat commentary).
