The most successful product launch in Apple’s history is how chief executive Steve Jobs described news that more than 1.7 million iPhone 4s were sold within three days of its launch.

The Apple boss then apologised to customers who were turned away “because we did not have enough supply”.

The iPhone 4 is currently only available in five countries - the UK, USA, France, Germany and Japan.

An additional 18 countries will be added to the list by the end of July.

The iPhone 4 features FaceTime, which is said to make video calling easy, and carries a new Retina display, described as the highest resolution display ever built into a phone.

Other details include a 5 megapixel camera with LED flash, HD 720p video recording and a stainless steel and glass casing described as the thinnest smartphone in the world.