In the 1916 War Office reorganisation which created MI5, H Branch had responsibility for the secretariat, registry and administration.
In MI5's 1988 structure, H Branch had been recreated with responsibility for overseas liaison; training; finance and audit.
In 1990, P Branch founded by Sir Antony Duff to review the service's organisation was wound up and its policy and planning functions incorporated into H Branch. In February 1990, Duff's successor Sir Patrick Walker tasked officer H1/0 to produce a strategic review of the Service. The result a year later was greeted with little enthusiasm within the Service. Jonathan Evans, then H1B/1, recalled a 'stormy' management board meeting at which Walker clashed with the MI5 legal advisor David Bickford.
Stephen Lander became Director of H Branch in 1994. According to official MI5 historian Christopher Andrew, Lander took the "risky but ultimately successful" decision to upgrade MI5's troubled Unix-based word processing system GIFTED CHILD, (nicknamed SPOILED BRAT) to a Microsoft-compatible system.
Authors Mark Hollingsworth and Nick Fielding offer a more critical account of the episode. They report that MI5 spent four years attempting to develop an in-house system codenamed GRANT before Lander unilaterally decided to scrap the project, which had cost £25 million, in 1995 and buy an off-the-shelf Windows system. Only 40 per cent of MI5 staff had access to the new system by early 1997.
- You have to go through a deputy assistant director of the branch, then an assistant director, a director, over to H Branch [Corporate Affairs], back to the desk officer, back to H Branch and then the Deputy Director General would see it. Finally [after his or her approval] you could probably go ahead.
The following list is taken from the 2003 edition of Hollingsworth and Fielding's Defending the Realm: Inside MI5 and the War on Terrorism and may now be somewhat dated.
- H1 and H2: Liason with Whitehall, the police and the media, covert financial enquiries, management policy including information technology.
- H4: Finance.
- R2: Main Registry
- R5: Restricted 'Y-boxed' files.
- R10: Registry for temporary files.
- R20: Administers GCHQ material.
- Stephen Lander 1994-circa 1996
- Jonathan Evans Former H1B/1
- Christopher, Andrew, The Defence of the Realm, Allen Lane, 2009, p.864.
- Mark Hollingsworth and Nick Fielding, Defending the Realm: Inside MI5 and the War on Terrorism, André Deutsch, 2000, p.54.