Shit just got real. Steve Jobs has penned an aggressive, detailed explanation of exactly why he refuses to implement Flash on the iPad and iPhone, and shed some light on the widening gulf between the two once-friendly companies.

He runs down a laundry list of reasons why Flash will never come to Apple's mobile products, addressing many of the points made by Flash proponents. He addresses openness, access to the "full web", security and performance, touchscreens and the fact that Flash is cross-platform, concluding with the statement: "the mobile era is about low power devices, touch interfaces and open web standards – all areas where Flash falls short".

In openness, Jobs claims out that Flash is proprietary and states that he'd rather use HTML5, CSS and Javascript to render the web instead. He says: "While Adobe’s Flash products are widely available, this does not mean they are open, since they are controlled entirely by Adobe and available only from Adobe. By almost any definition, Flash is a closed system".

Jobs then talks about content that Apple devices can't access without Flash - saying that it's not as much as people claim. He lists various video services that are accessible on Apple devices, including YouTube, but claims that "there are more games and entertainment titles available for iPhone, iPod and iPad than for any other platform in the world". That's simply not true, Stevie - the PC has the most by a long shot.

He then goes on to talk about security, claiming: "Flash is the number one reason Macs crash", and adding "We don’t want to reduce the reliability and security of our iPhones, iPods and iPads by adding Flash". He also talks about performance, saying that he's never seen Flash performing well on a mobile device.

He then rips into Adobe over battery life concerns, due to the claim that most video in Flash is decoded by software, rather than using the more recent H.264 codec. Jobs highlights the issue that Flash is designed for mice, rather than touchscreens and that "rollovers" just aren't possible with a touchscreen.

But Jobs says that the most important reason why Apple does not and will not support in its mobile devices is that it's adding an extra layer of code and software come between content and users. He explains: "If developers grow dependent on third party development libraries and tools, they can only take advantage of platform enhancements if and when the third party chooses to adopt the new features. We cannot be at the mercy of a third party deciding if and when they will make our enhancements available to our developers".

He adds: "Everyone wins – we sell more devices because we have the best apps, developers reach a wider and wider audience and customer base, and users are continually delighted by the best and broadest selection of apps on any platform". Everyone except Apple's rivals, of course.

The blistering assault on Adobe's technology is a painful read, but looking between the lines a little, the one company he mentions a few times but never criticises is Google, heaping praise on its Chrome browser. Has Jobs thawed a little on the other one-time Apple ally whose relationship has soured of late?

Are Jobs' comments fair, honest and correct? Is he right to take a stand against a technology that he considers not fit for purpose? Or are they ignoring a reality that Flash has too wide a base of support from content owners who are growing impatient for the most popular smartphone platform to allow access to that content? Read Dan Pocket-lint's thoughts, and then tell us your opinion on Jobs' sermon on the mount in the comments.