Below I set out the relevant part of the response from the Cabinet Office dated 20th September 2003. I've edited out the routine material about how to ask for a formal review etc.
Following a search of our records, I must inform you that the Cabinet Office, which includes the Prime Minister's Office, does not hold information relevant to your request.
So, it seems that the Cabinet Office is asking me to believe that it doesn't know whether or not the COBRA procedure was activated on 17th and/or 18th July 2003 or not.
Not suprisingly, I've lodged a request for a formal review of the response dated 20th September 2011.
My working hypothesis is that COBRA was activated and the Cabinet Office doesn't want to admit that.
I could be wrong.
If COBRA wasn't activated on 17th and/or 18th July 2003 in relation to the disappearance and death of David Kelly, why not just put a simple "No" in response to question 1. and question 2.?