Sales of Android handsets have overtaken the iPhone for the first time, according to data from market research firm Nielsen.

Over the last six months, Android has secured a 27 per cent share of smartphone subscribers to nudge ahead of Apple. The figure is revealed in a Nielsen blog post, and while the post does not mention iPhone’s share over the same period, other sources put this as 23 per cent. More stats, this time from Canalys, suggest that shipments of Android phones grew by a massive 886 per cent year-on-year in Q2 2010.

The Nielsen post also reveals, however, that iPhone users are more loyal than oners of Android phones. Among current subscribers thinking of buying a new device, the iPhone remains the most desired handset, finding loyalty with almost 90 per cent of current iPhone users and also enticing 21 per cent of Android owners and 29 per cent of Blackberry owners to consider switching to Apple. Android’s loyalty among switchers (71 per cent) outperforms Blackberry (42 per cent). Half of BlackBerry users say they could potentially choose an iPhone or an Android handset as their next device.

Finally, the post reveals that smartphones now account for 25 per cent of the US handset market, a 2 per cent increase on the previous quarter.