For those of my generation a defining moment was the vandalism of the Blue Peter Garden. As Percy Thrower stomped around demanding the return of the cat a certain amount of innocence was lost.
For a later generation the dismissal of Richard Bacon over d**gs, and the formal apology to the children, had a similar effect.
Both though involved external factors: the vandals (rumoured at one point to include Les Ferdinand) ; and Bacon himself. The programme itself remained above the controversy and by prompt actions maintained its integrity.
Well the current generation of Blue Peter viewers have their own scandal and the programme makers themselves are at its heart: Blue Peter is part of the great phone-in controversy. They faked results. If not even Blue Peter is free from the scourge of interactive phone-ins and, worse, faking the results of interactive phone-ins, what hope for the rest of society. It would never have happened under Biddy Baxter.
Shep must be turning in his grave.