Technology Monitor

Jobs, Apple's chief executive, told the Worldwide Developers Conference in San Francisco that iPhone 4 was "the biggest leap forward" since the original iPhone.

The new iPhone 4 is made from glass and stainless steel and features a five-megapixel front-facing camera with an LED flash. The screen on the new iPhone is four times the resolution of the display on the current iPhone 3GS, and iPhone 4 can also record and edit high definition video.

Steve Jobs demonstrated the FaceTime video-calling feature of the iPhone 4 by calling Jony Ive, Apple's chief designer.

The iPhone 4 will be available in the UK on June 24, in a choice of black or white. Apple has not yet revealed pricing and upgrade details.

"When you hold this in your hands, it's unbelievable," said Jobs. Details of the iPhone 4 leaked weeks ahead of today's official announcement, after a prototype device was dropped in a bar, and found its way into the hands of Gizmodo, a gadget blog.

"Stop me if you've seen this before," joked Jobs as he showed off the new device.

The iPhone 4 uses Apple's own A4 processor, which Jobs said gave superior speed and performance, as well as a better battery that will allow users to go for longer between charges. There's also a gyroscope built in to the device, which allows movement to be measured even more precisely, and could inspire a new generation of iPhone games, said Jobs.

Apple also gave more details about its new operating system for the iPhone, iPad and iPod touch, known as iOS4.

The software update will bring multi-tasking to the iPhone, allowing users to run multiple applications and programs simultaneously, and will also enable users to organise their applications in to folders.