Apple will have been planning this succession for a long time.

Rumours were circulating for a while that 65-year-old Tim Cook was thinking about stepping down, and while a few potential replacements popped up, the name which stuck was the firm's vice president of hardware, 51-year-old John Ternus.

I had an informal meeting with him in the UK recently and I asked him then whether he really was heir apparent to the Apple throne.

He laughed and very smoothly gave me what's known in the newsroom as a "politician's answer" - that is, he didn't actually answer the question at all.

Instead, he enthused about Tim Cook's leadership. But there was no other obvious reason why I was suddenly invited to have coffee with him at that moment, some 25 years after he joined the firm.

I found Ternus polite, friendly, and everything he told me was perfectly delivered, if a bit bland.

I wish I could tell you I got some good gossip, but there wasn't a single unguarded moment. Apple is frustratingly good at curating to the letter what it chooses to say, even in private.

He may have been able to bat off my questions, but Apple - despite its colossal success - faces some serious challenges.