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Post Office and Successors: Investigation Department

Identity Statement

Reference code(s): GB 0813 POST 120 Series
Held at: British Postal Museum and Archive: The Royal Mail Archive
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Full title: Post Office and Successors: Investigation Department
Date(s): 1836-1995
Level of description: Series
Extent: 537 items
Name of creator(s): Post Office


Administrative/Biographical history:

POID was founded in 1793, when the Postmaster General accepted some responsibility for the detection of domestic crime. The first records mention that an Anthony Parkin, private solicitor, acted regularly on behalf of the Postmaster General detecting offences committed by clerks, sorters and letter carriers, who had committed crimes such as taking bank notes and bills of exchange out of letters or other fraudulent practices.

The Post Office investigation work remained the responsibility of the Solicitor until 1816, when it was transferred to the Secretary's Office. It was later to be called 'The Missing Letter Branch'. As early as 1823, the Post Office investigators were seconded by chimney-hatted Bow Street Runners. Shortly after 1829, when the Police force was founded by Sir Robert Peel, Metropolitan Police officers were seconded to Post Office detective work and remained so until 1976. In 1848, an office was especially created for investigations duties. Investigations became the role of the Post Office Inspector General who could call on the assistance of a clerk in the Inland Office. The Missing Letter Branch continued to operate but, as before, its duties were restricted to missing letters only. Ten years later, in 1858, the post of Inspector General was abolished and the Missing Letter Branch was reorganised as well as strengthened by four Travelling Officers in charge of investigations seconded by two Police Constables acting as Assistants. By 1861, there were five officers who were given permanent status. In 1869, the Missing Letter Branch underwent another reorganisation and the department was put under the principal Travelling Officer - who became Clerk for Missing Letter Business - and made a distinct unit of the Secretary's Office.

In 1883, the Missing Letter Branch was renamed 'the Confidential Enquiry Branch' and the officer in charge given the title of 'Director'. By 1901, the duties of the Confidential Enquiry Branch were restricted to 'enquiries' only and any other duties were transferred to other branches of the Secretary's office; the staff comprised then solely of the Travelling Officers, managed by their Director. In 1908 the unit once again changed its name to 'the Investigation Branch'. The Secretary's office ceased to exist and the post of Secretary was replaced by that of 'Director General'. In 1934, the Post Office underwent a radical reorganisation which eventually affected the Investigation Branch in 1935. The Secretary thus became one of the administrative departments of the new Headquarters structure. In 1946, the name of the head of the Investigation Bureau changed from Director to 'Controller'. In 1967 the Investigation Bureau became known as 'Investigation Division' or 'Post Office Investigation Department' dealing with the investigation of Post Office crime and in particular theft from mail, by the deployment of civilian detectives with the full knowledge and approval of Parliament, the Home Office and the Courts.


Scope and content/abstract:

Papers of the Post Office Investigation Department (POID), consisting of reports, instructions, memoranda, annual reports and research notes.

Access & Use

Language/scripts of material:

System of arrangement:


Conditions governing access:

Public Record

Conditions governing reproduction:

Photocopies/photographs/microfilm are supplied for private research only at the Postal Heritage Trust's discretion. Please note that material may be unsuitable for copying on conservation grounds, and that photographs cannot be photocopied in any circumstances. See our published policies for full details. Researchers who wish to publish material must seek copyright permission from the copyright owner.

Finding aids:

A Guide to the Royal Mail Archive

Archival Information

Archival history:

Immediate source of acquisition:

Records transferred internally from Royal Mail.

Allied Materials

Related material:

POST 23 Inland Mail Services; Letter Post: POST 23/13-66; Missing Letting Branch case papers, 1839-1859. POST 30/1492 Confidential Enquiry Branch (GPO): Revision, 1907. Historical summaries of Branch workings and grades employed, 1793-1907. POST 74 Solicitor's Department; POST 74/199-203 Prosecutions in England and Scotland, 1800-1896, POST 74/204-344; Prosecution Briefs in England, Ireland and Wales, 1774-1934. POST 122/13084 Investigation Branch Annual Reports 1957/58-1966/67.

Publication note:

Description Notes

Archivist's note:

Rules or conventions:
Compiled in compliance with General International Standard Archival Description, ISAD(G), second edition, 2000; National Council on Archives Rules for the Construction of Personal, Place and Corporate Names, 1997.

Date(s) of descriptions:
28/03/2011 EAD validated May 2011

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