Apple’s lawyers have been getting very hot under their (turtleneck?) collars of late and I put the reason down to one thing – Android.

The big legal news out of Cupertino HQ is that Apple has decided to throw the rule book at rival phone handset maker HTC and see how much of a bruise it can create. Apple has accused the Taiwanese company of stealing its technology and using it to make phones such as the Google Nexus One.

Apparently Apple’s legal eagles have spotted 20 patents that they believe HTC has infringed, and they’re ready to hit the courtroom to prove it.

Meanwhile Google has waded into the growing brawl, backing its hardware partner HTC. It’s all starting to look like the kind of fight that could shape the booming phone market for years to come.

So why has Apple decided to take such action? Well, according to chief executive Steve Jobs, it’s because innovation is fine, but stealing other people’s technology is not.

Now, no one is going to argue against that logic, and a lot of patent lawyers are going to bill hundreds of expensive hours as they try to figure out if that's what’s happened in this case.

But it’s at a much higher level than patent law where the real battle is happening. Apple is scared stiff its iPhone is about to lose significant ground to handsets running the rival Android operating system, and its prepared to do anything it can to fight the trend.

The signs that the iPhone's heyday might soon be over are already appearing.

First there's the growing disquiet among software developers over the way in which Apple routinely bans certain iPhone apps from its online store for little or no good reason. What's the point in spending time and money developing something when Apple can ban it at a whim?

Then there's the growing chorus of approval for the flexibility and openness of the Android platform and the phones that run it. Such openness equals innovation and customer choice. Just look at the range of handsets already on the market, with dozens more in the wings.

While Apple is still ahead of Android when it comes to market share, the gap is closing. Recent research by advertising company Admob found that, in January, 47 per cent of download requests in the US came from iPhones while 37 per cent came from Android-powered devices. Expect to see those numbers change throughout this year.

So, what has Apple got to lose from its court actions? Nothing really, apart from some legal fees - and if it succeeds, it could put some serious brakes on the growth of Android.

Either way, it's a battle that's going to be very interesting to watch, and one that could influence what smartphone you have in your pocket as you head to work during the next couple of years.