Launch adds to Apple's core appeal

The new iPhone seems like the slightest of improvements over last year's model. Apple's handset now has a 1GHz dual-core central processor but others are faster. And the iPhone display is still smaller than other phones.

So why is the iPhone 4S, without a new design, set to conquer? Apple has given the phone a big internal makeover. Apple's secret weapon is called Siri, a voice-activated personal assistant. Ask if it's going to be chilly in London tomorrow and it'll say "no, seven degrees doesn't seem all that cold". You can even ask it to remind you to pick up your dry cleaning when you leave work. When the phone's GPS spots that you're moving, it pings you a message. The biggest problem of the iPhone 4, signal quality, has also been fixed. The retooled antenna system is superb. Overall, when you look closely, it's not such a gentle upgrade after all.