Royal Mail Group Security

Royal Mail Group Security (RMGS), the investigative and security function of Royal Mail, is the oldest functioning law enforcement agency in the world. Prior to the full divorce of Post Office Limited and Royal Mail in 2012, RMGS was a branch within the larger Royal Mail Group Centre, operating alongside Post Office Security and Investigation Services (POSIS) to maintain proper function of The Post Office. RMGS was bifurcated from POSIS in 1999 – before that, POSIS was the sole investigative agency for the entire Royal Mail Group, with its executive board at headquarters known as the Security and Investigation Executive (S&IE). Before the year 1969, the Royal Mail was literally the "property of the Crown," and its agents were all officers of the State. However, since 1969 and the creation of the Statutory Corporation, their enforcement powers have been more limited.

Known before 1996 as the Post Office Investigation Division (POID), before 1967 as the Post Office Investigation Branch (IB), before 1908 as the Confidential Enquiry Branch, before 1883 as the Missing Letter Branch, and before 1816 by the nickname of The Enquirers, it has been a function of the British Postal system since 1683. For over three centuries, it has investigated those alleged criminals who have committed package theft, mail robbery, mail fraud, highway robbery, sedition, terrorism, communist activities, murder, smuggling, and other crimes involving the post. It has also been the primary investigative authority over employees of the British postal system, and until 1836, the Missing Letter Branch pursued the death penalty against any postal carrier who had stolen a single letter.

IB was the principal investigating agency into the incidents of the Great Train Robbery, directing the efforts of the Buckinghamshire Police, the Train Robbery Squad, and the Metropolitan Police. POID was especially involved in the pursuit of the serial killer Donald Neilson.

From 1968 onward, after the disastrous handling of the General Post Office by John Stonehouse (who turned out to be a Czech-KGB spy, and faked his own death in 1974), Neoliberal and Libertarian elements of the Liberal Democrats and Conservatives undertook decades-long efforts at privatization of the Post. In 1996, a massive attempt to fully privatize the British postal system was undertaken. Despite the failure of this attempt, it still resulted in the effective dismantling of POID in what was called a "modernization" program – one that would for the successors of POID – RMGS and POSIS – be the inception of the disastrous British Post Office Scandal, known today as "the greatest miscarriage of justice in British history." Confusingly, today, Royal Mail is what Brits call the company that manages the bulk of their postal services, while Post Office Limited is an entirely different organization that only oversees a very limited scope of postal services.