Apple CEO Tim Cook trolls Microsoft and Google at WWDC 2014, ends up with egg on face

After his numerous gags made at rival technology companies' expense at WWDC last week, Apple CEO Tim Cook has been brought down to earth with a bit of a bump.

The big boss, who isn't exactly renowned for his social media presence, decided to tell his Twitter followers about a recent visit he paid to an Apple production factory in Austin.

Read more: Apple, Microsoft, Google and Yahoo: Tech's top 10 Judas moments

"Watching the Mac Pro come together in Austin yesterday,thanks to a team loaded with American manufacturing expertise," his update read.

Apart from the lack of a space between the comma and the word "thanks", and the shameless US plug, it initially looks like a perfectly well-constructed, if a little dull, tweet.

However, Cook decided to attach an image to his update, and he did not choose wisely.

The picture (above) shows him with a bunch of factory workers, standing before a pair of iMacs which appear to be running the Windows XP OS. Other Twitter users were quick to point out the gaffe, with one replying, "the iMacs in the BG are running WINDOWS. How dare you."

Those who tuned in to the WWDC keynote last week will remember that Cook took it upon himself to heavily criticise both Microsoft's and Google's operating systems.

Cook mocked Microsoft for the lukewarm reaction to Windows 8 and rounded on Android for its fragmentation, saying, "Some [customers] are on [Android] from four years ago – that's like ancient history!"

Read more: WWDC 2014 keynote as it happened

Since Windows XP was launched in 2001 and is no longer supported by Microsoft, you might argue that Apple's factories are living in the prehistoric age.

Note to Tim: if you're going to make a point of ridiculing others, either watch your own steps carefully or be prepared to face a rather embarrassing backlash.