I-SIS is a SIS/BritishCrown parallel branch.

https://www.linkedin.com/grp/post/154534-6051372620161503236
It is institutional duty of MI6/SIS creating  and using terrorism everywhere in the world.
It is centuries it is doing that everywhere in the world.
The destabilization of Iraq and Syria, idem Libya etc, is British and US work.
Surely, conspiracy theorists claim that terrorism come from obscure forces and from the skies.
Tales!
Independent terrorism in IMPOSSIBLE. It could not exist.
Terrorism is ALWAYS work of governments, firstly of the two main world Empires, the British and the US ones.
ISIS is apparently sponsored from British and/or US clients as Saudi Arabia, Qatar, Turkey, Israel.  ...Puppets...
Oil is currently sold from ISIS.
Its weapons come from British, US and Israeli bases.
Its recruiting structure is kept hidden and covered, as well as its funding, even its internet servers are protected, while the British SIS checks and controls ALL the world electronic communications.
ONLY those checking and controlling can provide cover to terrorist organizations.    

No, the British SIS is NOT "involved".
The British SIS has created and is managing ISIS.
ISIS ruthlessness, use of advertising mechanisms, media and social networks presence, use of special forces operational techniques, are typically British.
I-SIS is a SIS/BritishCrown parallel branch.