How proven was the Sea Harrier defence concept in 1980?

How could Sea Harrier be described as effective against long-range Soviet naval aviation and very fast missiles?

It was still a theory: Sea Harrier was the planned outer layer, not demonstrated proof against the full Soviet threat.

The government speech presents Sea Harrier as the first layer protecting anti-submarine groups from Soviet naval aviation. A viewer questions how confidently the aircraft could be called effective against long-range bombers and very fast missiles. The answer is deliberately restrained: that was the theory. The exchange distinguishes a planned role in a procurement system from combat-proven performance against the full threat used to justify it.