Harry Shepherd (an alias), the minister for intelligence - an incredibly secret post within the government - has emerged from the shadows under intense scrutiny to reveal why MI5 and MI6 are not called MI1 and MI2.
"You see," said Shepherd (not his real name), "There are three armed forces. The Navy, the Army and the Airforce. So we did have MI1, MI2 and MI3 as they were in charge of policing the army, navy and airforce respectively."
According to Shepherd (still not his real name), when the military intelligence units were set up in the late 1940s, each branch of the armed forces were given their own military intelligence unit. It was quickly discovered that a unit was needed to police all three for cross armed forces disputes, and this was named MI4.
When a country wide intelligence service was a requirement, it was natural to call it MI5, which was quickly followed by MI6 for foreign affairs.
"It was a nice, neat hierarchical structure," said Shepherd (definitely not his real name). "Each intelligence unit with a higher number had a wider area of responsibility."
What people are largely unaware of is that MI7 is responsible for policing all the other intelligence units.
"They [MI7] are the secret police for the secret police, if you like," laughed Shepherd (okay, it is his real name, but he pretends it's not in a kind of double bluff that spies enjoy).
Given its hierarchical nature, should humans ever expand into the universe at large, then the system is ready to expand with them.
"We can create an MI8 for the solar system, and an MI9 for the galaxy," said Shepherd (actually, not his real name, it was a triple bluff). "MI10 would be responsible for the whole universe. And if we invent time travel, we can have MI11 for that. The whole of time and space. Perhaps Doctor Who is a member of MI11!"
Under the freedom of information act, it was finally revealed that MI1, MI2, MI3 and MI4 were all disbanded in 1978 to become divisions within MI5.
"It cost to much to run all those intelligence gathering organisations," Shepherd (his real name is Phil Potts) admitted. "Besides, we could never keep track of who was working for whom."