Ever since Apple unveiled iOS 14 in the summer, Facebook has been protesting against new privacy measures in the software update. The social network was particularly aggrieved by a feature that asks users if they are happy to be tracked.

Facebook has taken out full-page adverts in major US newspapers to argue against the change and claim it will harm small businesses - while declining to mention that Facebook's own business model is also threatened.

But Apple has not taken the criticism sitting down. Last week we reported the company's statement, in which it called the changes "a simple matter of standing up for our users". And now CEO Tim Cook has posted his own response on Twitter, pointing out that Facebook can continue to track users between apps and websites just as before, but that in iOS 14 they must ask the user for permission first.

Since we wrote this article the Electronic Frontier Foundation, or EFF, has waded into the dispute to offer its support for Apple and to call Facebook's campaign "laughable". EC competition czar Margrethe Vestager, on the other hand, has warned Apple that its rules could become an antitrust issue if it doesn't apply them consistently - seemingly responding to Facebook's caricature of Apple's position rather than what Apple has actually said it will do.

Facebook and Apple have been jousting over the issue of user privacy for years, since their business models approach it from such a different angle, but this year the issue has become more prominent than ever.

Instagram, which Facebook owns, blamed a bug when iOS 14 warned users that the camera was active when they were just scrolling through photos, and Facebook vigorously objected when iOS 14's new privacy features were unveiled in the summer. (Apple CEO Tim Cook says the new tracking rules will take effect 'early this spring'.)

Apple, by contrast, made privacy the central theme of its iPhone adverts in the autumn.

The two firms' relationship has become increasingly rancorous in recent years. It's been revealed that Mark Zuckerberg once told his team that "We need to inflict pain" on Apple, and although his public statements have been more restrained he rarely misses an opportunity to take issue with Apple's positions.

This article originally appeared on Macworld Sweden. Translation by David Price.