When Siri was launched by Apple in 2011 - they chose a female voice in the USA but a male voice for the UK market. Jon was that voice - the original UK voice of Siri. Now there are numerous Siri voices - but like James Bond and Sean Connery - there was only ever one original.
You'll find Jon's synthesised voice on a whole host of other gadgets from Sat Navs for TomTom and Garmin and Jaguar LandRover vehicles to Apps like Waze. It's used by a whole range of IT devices to read text aloud on smartphones and computers. This allows people who are sight impaired to access everything from emails and websites just as easily as regular sighted people do. Jon's voice is usually nicknamed "Daniel" if you want to apply it to your app or computer.
Siri often makes the headlines - and I'm often interviewed about the job. Here's one of the latest interviews:
Jon is often asked about whether he enjoys being Siri - and of course the answer is "yes". But what gives him the most pleasure are emails like the one below from Rik. Enabling people to use the web and email when they don't have have the ability to see as well as others can is really empowering. That's the best bit about being Siri for Jon.
If you'd like to know some more about the other Siri's that have been used on the iPhone, the Guardian newspaper can tell you more in this article.