I won’t reiterate the many general arguments against the death penalty here, but consider these. Collins tried to justify the execution of Saddam by citing the brutality of Saddam’s regime. The thing is, you don’t demonstrate the wrongness of a brutal regime by exercising the most brutal form of punishment. You don’t win that way: at best you draw, and who wants to draw with a dictator? You win by showing that you’re better than that; by behaving in a civilised way.
He went on to say that it’s “incoherent” that Britain should have nuclear weapons, but not have the option to execute terrorists. I see absolutely no logical connection between the two, and neither did Michael Portillo. Nor could Collins make the connection in a way that made any sense.
Using the death penalty isn’t a sign of strength: it’s a sign of weakness. The truly strong can both show mercy, and behave in a way that separates them from the caveman.