Android downloads have passed the 4.5 billion figure - up 3.5 billion compared to this time last year.

The boom in Android popularity is highlighted by the fact the last billion downloads occurred in just 60 days.

Speaking at the launch of Google's "Sites Mobile Landing Pages - Google Mobilize", Ian Carrington, Google's mobile advertising sales director for northern and central Europe highlighted that whilst Apple celebrated 10 billion downloads back in January, the rate of Android growth should be enough to make the Cupertino collective sit up and take note.

"A year ago that [download figure] was one billion, and that first billion took two years to happen," he said.

Back in May, Pocket-lint reported how the Android Market was predicted to be on course to overtake Apple's App Store in terms of the number of apps on offer by August this year.

As it stood then, Apple had around 380,000 apps in the App Store and Google was offering almost 295,000 in the Android Market but crucially, the Android Market had 28,000 new apps added in April, whereas the App Store only increased by 11,000.

However, there were reports at the end of May that Apple had reached the 500,000 app figure so it's not clear when, or indeed if, Google may now overtake its big rival (current estimates for the Android market stand at around the 400,000 mark).

What is clear is that the rise in Android popularity and the wealth of Android devices in the market (at a wide range of budgets) does pose a serious threat to the Apple app stronghold.

See also - 100,000 iPad apps now in the App Store