I recently went for a colonoscopy at my local unit after presenting with a change in bowel habits. Follwoing a massive Calprotectin reading i got in to the unit fairly quickly. I prepared as required and scored top score on the 'bowel cleanliness' chart before the procedure took place. The procedure was done by a qualified doctor ( in training for this particular procedure ) but she was being overseen by the registrar.I  was on gas and air. The procedure started fine and a polyp was removed from the first third of my colon. Then when trying to progress however there was clearly a problem. I don't mind what anyone says I have a good pain threshold but what followed was beyond anything i have felt in my entire 65 years. The registrar said I should suck on the gas and air but it quite simply did not do a single jot for the absolute abdominal agony. I was surprised that the registrar obviously thought I was some sort of wimp and wanted to just plough on when this massive 'red flag' was clear for all see and hear (especially when i was screaming) I told him to STOP. He wrote my report up that I had abandoned the procedure. One Polyp removed only one third of my colon examined. Put me on sepositories for 6 weeks and an appointment back in Sept this year.   Wondered if i could insist on a ct scan next time? Sorry if thats put people off but no point making it all rosey when it is not.