John McLeod Scarlett (born August 18, 1948) is head of the British Secret Intelligence Service, commonly known as MI6. Prior to this appointment, he had chaired the Cabinet Office Joint Intelligence Committee (JIC), a body comprised of the heads of the UK's Intelligence Services and other senior intelligence staff.

Fluent in Russian, Scarlett was educated at Epsom College and Magdalen, Oxford where in 1971 he received a first class degree in History. Shortly afterward he was first recruited by MI6 where he served in Moscow, Nairobi (1973-1976) and Paris.

In 1994, after a tit-for-tat row between the UK and Russian authorities, Scarlett was asked to leave Moscow where he had been MI6's "station chief".

He retired from MI6 as Director of Security and Public Affairs in 2001. He took on the role of head of the JIC (the UK Government's central organisation for intelligence assessment) just three days before the events of September 11th shattered any prospect of a post-Cold War peace dividend in the world of intelligence gathering.

The normally secretive intelligence services were thrust into the public gaze in the Summer of 2003 after the death of the eminent government weapons expert, Dr David Kelly. Kelly had killed himself after being exposed as the source of allegations that the government had "sexed-up" intelligence regarding existence of Weapons of Mass Destruction in Iraq prior to the 2003 Iraq War. The "classic case" was the claim that Iraq could launch Weapons of Mass Destruction "within 45 minutes of an order to do so" - Dr Kelly had privately dismissed this as "risible".

Scarlett gave evidence at the subsequent inquiry into the circumstances surrounding Kelly's death. It became clear that Scarlett had worked closely with Alastair Campbell, then the Prime Minister's Director of Communications and Strategy, on the controversial dossier, with Campbell making drafting suggestions which the inquiry found may have "subconsiously influenced" Scarlett and the JIC. This influence may have had deleterious effects on the quality of the assessments presented in the dossier. For instance, the Intelligence and Security Committee made several criticisms in their report "Iraqi Weapons of Mass Destruction — Intelligence and Assessments":

"As the 45 minutes claim was new to its readers, the context of the intelligence and any assessment needed to be explained. The fact that it was assessed to refer to battlefield chemical and biological munitions and their movement on the battlefield, not to any other form of chemical or biological attack, should have been highlighted in the dossier. The omission of the context and assessment allowed speculation as to its exact meaning. This was unhelpful to an understanding of this issue."

Such wider questions about the quality, handling and presentation of intelligence will be examined further in another inquiry which was announced by the British Government on February 3, 2003. Scarlett's role as chair of the JIC is expected to come under further scrutiny.

Despite this controversy, Scarlett moved from the JIC and returned to MI6, appointed by Tony Blair as its head, C, on May 6, 2004.