See also: Google Android review
However, the website's stock of 1,000 phones was purchased within three hours, forcing eXpansys to put a 'sold-out' notice on the Milestone.
eXpansys told Pocket-Lint: "Within 3 hours of the product being listed as 'in stock' on the eXpansys site it sold out. This makes the Motorola Milestone the fastest selling gadget in the website's 11 year history, even more successful than the iPhone".
The Motorola Milestone has a 3.7in capacitive touchscreen display, slide-out qwerty keyboard and 1GB of onboard RAM. It has a 533MHz ARM processor and runs Google's Android mobile OS.
Google Maps and a built-in GPS module means the handset can be used for navigation, while users also benefit from a 5Mp camera with a 5x zoom. It can also record video at 24fps (frames per second).
Additional storage can be added via the Milestone's microSD card slot, which can accept cards of up to 8GB. Wi-Fi, Bluetooth, GPRS, 3G and HSDPA connectivity are all offered.
However the retailer said the phone is now back in stock. It costs £449 for a sim-free handset or £50 with an 18-month contract on T-Mobile.
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