The showrunner last week publicly responded to reports suggesting that ratings for the ITV1 soap have fallen dramatically.
Roache, who has played Ken Barlow in the show since it launched in 1960, defended Collinson's work on ITV's This Morning.
"Right, two points to make," he told hosts Phillip Schofield and Jenni Falconer. "One is, is that one of the hardest tasks of the producer is to move the Street forward into what is socially acceptable.
"Times change. If you showed an episode we have today in 1960, we'd be off the air, banned; it'd be something horrible."
Roache explained: "The producer has to do that [by] bringing in the new, without offending the old. So every so often, a senior member, well-meaning , will say that the Street isn't what it used to be. It's sad that that happens, but it does. There was a big article like that last week.
"I understand why [Brian Sewell] said that, but this is part of keeping it new. A journalist jumped in on this bandwagon and what he did was, he took the current ratings - which are about 8 million roughly - compared it to a one-off special which went out, highly publicised at 9pm and got 10 million, and said that the Street is slipping in the ratings."
Defending the ratings, the 79-year-old said: "If you look at the ratings for this time last year, we are 8% up. Far from going down, the Street is going up. Now, a lot of this is due to the live episode and the tram crash, which brought in a lot of new viewers and many have stayed with us. We're stronger than ever, better than ever.
"I'm enjoying it more than ever. I think last year was the best thing it ever did. While I can do it, while they want me, I'll be there."
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