One of the most clandestine of all British special operations units is E Squadron. It’s a small unit of United Kingdom Special Forces (UKSF) operatives handpicked to work for the Secret Intelligence Service (SIS), better known as MI6. Both the UKSF Directorate and Secret Intelligence Service use E Squadron to carry out clandestine activities. They say E Squadron is the modern-day incarnation of a long-rumored MI6/UKSF unit known only as The Increment.

It can be safely assumed the unit is manned by the most experienced members of the UKSF, selected from such units as the Special Air Service (SAS), Special Boat Service (SBS), and the Special Reconnaissance Regiment (SRR). They likely receive electronic warfare and logistics assistance from relevant attached components such as the 18 (UKSF) Signals Regiment. Resources such as RAF 7 Squadron Chinook helicopters, from the Joint Special Forces Aviation Wing (JSFAW), are undoubtedly available upon request.

Rumors of The Increment acting on behalf of the General Support Branch of Britain’s Secret Intelligence Service (SIS) have been circulating for years now. The missions tasked to The Increment are black ops: deniable missions that would be disavowed by the British government if compromised. These could include:

  • Secret military assistance to foreign powers
  • Clandestine insertion and extraction of intelligence agents
  • Covert reconnaissance/intelligence gathering
Special Boat Service (SBS) personnel and soldiers from the U.S. Army’s elite Delta Force pose for a photo during the December 2001 operation to kill Osama Bin Laden in the Tora Bora region of Afghanistan.

SAS and The Increment

Former MI6 agent Ian Tomlinson published a book titled “The Big Breach.” He claimed the Revolutionary Warfare Wing (RWW) of 22 SAS provides most of the manpower for The Increment. One of the crucial tasks of The Increment was close protection for SIS operators working on risky assignments. Other roles included hiding stockpiles of equipment in foreign countries as escape caches for SIS agents. The Increment would further facilitate hot extractions of SIS undercover operatives.

SBS and The Increment

The Special Boat Service’s (SBS) contribution to The Increment is rumored to include planting trackers on vessels docked in foreign ports. Operators in The Increment would likely need SDVs to ferry SIS agents to and from foreign coasts. SBS-trained Increment operators may work under aliases and carry the relevant commercial licenses to hire and operate boats such as fishing trawlers.

XW223, a Puma HC1. This particular aircraft features enlarged fuel tanks. It was rumored that this Puma was assigned to a secretive RAF unit known as S&D Flight, which supported UKSF/MI6 operations.

RAF S&D Flight

The Increment has a secretive Royal Air Force (RAF) unit dedicated to supporting their operations. Known as S&D Flight, it utilizes Puma helicopters from 33 Squadron and a C-130 from 47 Squadron. S&D pilots are recruited from other RAF special operations flights. A team from the SAS RWW would most likely also be deployed with the aircraft on operations involving The Increment.


The Increment does not work alone. Another supremely clandestine unit in the U.K. intelligence services is the UKN, a highly specialized surveillance unit also run by SIS. The UKN specializes in surveillance in foreign countries and it has been speculated that the unit acts as The Increment’s eyes and ears, identifying and tracking targets for operations.

E Squadron = The Increment

E Squadron’s task is to carry out clandestine activities for Britain’s foreign intelligence service, and its intelligence agents operate in countries around the world. They establish and run agents, form alliances with factions inside foreign countries, and collect intelligence from an extensive range of sources. Working in hostile regions has become a growing obligation since the commencement of the Global War on Terrorism, and MI6 now regularly relies on special operations escorts on their missions.