Google provided a glimpse of its Android operating system running on a mobile phone for the first time in Europe on Tuesday, in a limited viewing ahead of its imminent launch.

The device looked similar to HTC's Dream, rumored to be the first device that will have the OS, although bits of masking tape obscured any branding. T-Mobile's London office said Tuesday it is committed to launching an Android phone by the end of the year.

Mike Jennings, a development advocate for Android, pulled the phone from his pocket during a presentation at Google Developer Day, a one-day training workshop on Google's tools and products.

Jennings used the Android SDK (software development kit) to create an extremely simple application: a blue dot that bounced within the phone's ample screen space and moved as the phone was tilted, showing the device has an accelerometer, also a feature in Apple's iPhone.

"We're back to 1970s Pong," Jennings said to laughs, referring to one of Atari's first video games.

Google has been cautious about showing devices running Android. Jennings said he just recently received clearance to show a device since there has been "nervousness" about the OS's debut. Google's stock has been affected by Android-related news, he said.

When asked if he could make a call with it, Jennings said "Yeah, I could" without taking it out of his pocket. "I just want to show it off all the time but I can't," he said.

Part of Tuesday's teaser preview is to pique the interest of mobile developers to build momentum around Android, which enters a heated mobile market with competitors Symbian, Microsoft and Apple.

Apple's iPhone has been propelled to popularity in part by its applications store. Microsoft's Windows Mobile OS has at least 18,000 applications written by third-party application developers and Symbian has a wide array of applications.

"The only way we can compete is to get an array of developers," Jennings said.

Jennings thinks that Android is simply better than software from competitors such as Microsoft. Developers will be able to dig into its source code when it is eventually released, which gives deeper insight into how good applications should be built, Jennings said.

Google's terms of use for the SDK limits developers to running Android on their PC in an emulator. However, that hasn't stopped some developers from putting Android on Nokia's N810 open-source handheld devices. Those devices run Maemo Linux, and Android is based on Linux.

Jennings was asked about developers breaking the rules.

"What do I think about people that are already running Android on their phones who have hacked the SDK and have completely blatantly disregarded the terms of use in the SDK download and are breaking the law?" Jennings asked.

"I think it's pretty cool," he said to chuckles from the audience.