In order for an application to be allotted to the competent directorate, a preclassification must be made. The level of classification at this stage should be as general as practicable on the basis of a quick and cursory scrutiny of the document (e.g. the title and independent claim or claims). On the other hand, the level should be specific enough to avoid the need for any intermediate stage of preclassification before allocation to the competent directorate. The most appropriate level in the light of these considerations is usually that of the sub-class. Only rarely, when the sub-class is exceptionally large or heterogeneous and spread over different directorates, is preclassification to a main ("00") or sub-group necessary. This classification should be indicated by the use of the appropriate symbols in a space to be provided on the dossier.

The preclassification required for this first allocation should be made on the basis of the independent claims. If this results in preclassification in more than one sub-class, then whichever of these seems to be the most relevant to the claimed invention (or the invention first claimed, if there is lack of unity of invention) should be selected. This is the preclassification which should be indicated on the dossier.

In most cases no further classification is required to enable applications to be allotted to the Search Divisions within a directorate, but, where it is necessary, it falls within the authority of the examiner in charge of the field to arrange for such allotment in an expedient manner.