TangoAlphad you may be right but error / omission set aside , my question leans more on the procedural side . The reason i am asking is because quite frequently in LHR , a place were controllers very rarely ever make mistakes , take off clearance is issued in what seems to be less then the prescribed radar wake turbulance separation minima . It gets me thinking that there are other factors that come into play that we do not know .
I have to admit i did not pose the question in the manner i wanted but i was hoping i would get many replies that would resolve my question