A new attack from disgruntled iPhone users is putting Apple in the dock for locking iPhones to AT&T's network, claiming that such a lock is illegally anti-competitive.

The suit, filed in Northern California and picked up by CNet, argues that Apple's 2007 deal to lock iPhones to AT&T was in breach of the Sherman Act – a US antitrust law regulating anticompetitive conduct – and the Digital Millennium Copyright Act, which permits the unlocking of phone handsets, so the plaintiffs are seeking financial restitution and an undertaking that Apple will never act in such an underhand way again.

Customers who bought the first iPhone, the suit explains, entered into a contract with AT&T but were not told that they would be unable to use the handset with another operator, even after the end of the AT&T contract period or while travelling abroad, and that is in breach of their rights: "Apple has prevented iPhone customers from exercising that legal right by locking the iPhones and refusing to give customers the software codes needed to unlock them," the lawsuit reads.

Back in 2007 Apple had to offer mobile networks exclusive access to the iPhone as it was the only bargaining chip Cupertino had. The tactic proved hugely successful, playing operators off against each other to obtain outrageous deals (for Apple) in exchange for exclusivity, but it also put Apple in the hands of the operator, which is why Cupertino no longer plays the game that way.

AT&T's deal was, reportedly, for five years, but the suit notes that it actually ended in February 2011 when Verizon started selling iDevices.

The filing does note that customers managed to work around the lock as early as August 2007, and given such workarounds had been declared legal in a clarification of the DMCA, it begs the question of why the plaintiffs didn't just use such a method, but that's not the point.

Two individuals, Zack Ward and Thomas Buchar, both bought iPhones around 2009 and found that at the end of their AT&T contracts they couldn't switch networks, which is enough for a class action suit, even one which feels more like a punt in the dark than a serious accusation of wrongdoing. ®