iPhone 3GS vs iPhone 3G real-world battery test: Over 45 per cent better

To test voice calling over 3G, we rang each phone from a landline and pumped the dulcet tones of Radio 4 through the receivers to simulate a civilised chat.

The older 3G stayed tuned to Woman's Hour for 2 hours and 35 minutes before giving up the ghost.

The fresh-faced 3GS lasted 3 hours and 48 minutes until it was completely discharged.

So 3G calling definitely drains those batteries, but the iPhone 3GS lasted 73 minutes -- or 47 per cent -- longer.

Click through to see how it all stacks up to Apple's iPhone promises.