From what date were Building Control completion certificates issued?

I built a garage in 1986-7 and subsequantly extended it forwards in
2003, both tranches being with full planning permission and building
control inspections. I have a completion certificate issued for the
2003 addition but cannot recall being given one for the 1986-7
original. Council are happy (for 40 quid) to issue one as it was
completed under their supervision but when did BCO's start issuing
certificates?

Needless to say it is the sale of the house that is prompting this.

AWEM