Apple has unveiled the much-anticipated iPad that it said will ignite the e-books market.

Although much bigger, it has been compared to the iPhone in the way it looks and feels.

Besides being able to read e-books on the touch-screen tablet computer, users can also surf the internet, send emails and view videos.

Apple chief executive Steve Jobs called it a “revolutionary product” that would fill the gap between smart phones and laptop computers.

He threw down the gauntlet to rival Amazon, which produces e-book reader the Kindle, saying that the new Apple iBooks store and electronic reading functions “stand on the shoulders” of Amazon’s Kindle.

To begin with Apple will offer titles from a handful of publishers including HarperCollins and Penguin.

The device has a 9.7 inch touch screen and a price tag of $499 (£309) for a bottom-of-the-range model.