How howler 'headline headghgh' went global...and what might have caused the production clanger

This is how the Citizenstudios.blogspot website sent the Bedfordshire Times & Citizen front page howler 'headline headghgh' global:
"Thursday afternoon; I returned from work to see the Times and Citizen on my door mat, I took a picture of it on my phone and uploaded to Twitter.
"Sunday evening; that picture will have been seen by a recorded 57,000 people, reused on The Huffington Post, The Guardian and Photoshop Disasters, blogged and tweeted all over the world and available on a T-Shirt.
"But how did this happen, how do you cause a 'Twitter sensation'?
"The first thing I've learnt from all of this is, if something's interesting to you, then it's going to be interesting to other people, the challenge is getting it to a wider audience. I normally dismiss these kind of mistakes, I hate the Grammar police and the Design Police, it's the kind of self righteous nonsense that people hide behind when they've got no ideas of their own. But, I'm also a massive hypocrite, so I figured other people might want to see this huge, hilarious cock-up."
By selective tweeting and facebooking citizenstudios then sent 'headline headghgh' global.

• According to The Blog website: "A senior source inside Johnston Press has confirmed to The Blog that the now infamous ‘headline headghgh’ gaff was down to an ATEX error. The source, who does not want to be named for obvious reasons, said the front page of the Bedfordshire Times & Citizen’s mid-Bedfordshire edition was sent off with the correct headline in tact, but that somewhere along the line it reverted to an old version with the changes to both the headline and strapline being lost.
  
• "That meant the front page appeared with a templated version reading ‘headline headghgh’ and a strapline saying ‘Strapline for main story like this if needed’. The debacle, according to our source, has drawn the attention of bosses in Edinburgh, including chief executive John Fry. Questions are now being asked as to why the error was not picked up at the printers in Portsmouth where around 17,000 copies were printed before the presses were stopped. It is also rumoured that IT experts are to be sent to every centre around the country to make sure the system is being implemented correctly."
• See also: NUJ in protest to Johnston Press management: 'Stop making our papers look silly'