Apple launched its newest iBook laptop computer on Tuesday, an all-white machine that is thinner, lighter and cheaper than its predecessor.

The new iBook was unwrapped at Apple's headquarters by chief executive Steve Jobs. At 11.2in deep, 9.1in wide and 1.35in thick, the machine weighs in at 2.22kg - two-fifths lighter than Apple's existing consumer laptop, Jobs said.

The notebooks use a 500MHz Power PC G3 processor with 256KB of performance-boosting on-chip cache and offer five hours of battery life, according to Jobs. As well as being lighter the new iBook also has an improved screen resolution, at 1,024x768 pixels. "This has the same number of pixels as an iMac in its highest resolution," Jobs said.

The new iBook is priced at £1,099 and will be out in the UK in a couple of weeks.

"This does look like a breakthrough," said Martin Reynolds research fellow with analyst firm Gartner. "It's just like a portable iMac."