The 'Confidential' files are a continuation of the ordinary peace-time series PREM 1. PREM 4 has been created by a simple chronological separation carried out at a later date.
The original arrangement was in a number of broad divisions such as 'HOME' and 'FOREIGN', within which sub-divisions were created with the help of numbers, e.g. FOREIGN 2 - Poland. The divisions are distinguished in this list by the use of capitals.
There is no comprehensive list of the sub-divisions in use and it is not invariably clear what their subject titles were intended to be. Occasionally numbers appear to have been omitted from the series, although in general where a number is absent from this series it is due only to the non-employment of the sub-division during the relevant period.
Since the indexes (PREM 4/102-135) refer to the original numbers they are shown in brackets for each box. The reference numbers shown in the list are those of the boxes in which the papers were packed, and within the boxes, of the original folders or, sometimes, 'strings' in which the papers were assembled.
The production units are the former folders within the boxes and both the box-numbers and the sub-numbers must be used for requisitions. The original numbers do not form part of the reference.
Some cross-references have been inserted in the list, and others will be found in the files. In some cases a numbered sub-division contains two distinct topics, e.g. 'HOME 5' which contains both Defence/Security and Tours, that is, Prime Minister's visits in the United Kingdom.
In other cases a sub-division received no number, e.g. 'PRIME MINISTER - Deputations', which incidentally, contains material not connected with deputations as such, e.g. resolutions. Confusion also occurred where a sub-division became excessively swollen and gave rise to sub-sub divisions e.g. 'IMPERIAL 77 - India'.
Finally, new divisions were created when the need became apparent and this involved a change of title for some sets of papers, e.g. WAR 10a became 'RECONSTRUCTION'. This type of change may cause some difficulty in the use of the original index, but where such changes have been noticed they are noted in the list, and it should generally be possible to trace a changed title with the help of the indexes.