text: But Reaction Time is a bit of an unusual commission that left me, as producer, staring at a half-hour gap in the schedule and wondering what would fill it.
  It is the network's first programme made entirely on smartphones.
  The premise was simple on paper.
  BBC Radio 4 put a prompt on social media ahead of Valentine's Day: "Tell us a story about love," inviting anyone in the world to make a two-minute voice recording of their relationship story, on their phone, and email it in as an attachment.
  Then, I would knit the contributions into a half-hour of online dates, first loves, and bitter break-ups.
  I will confess to some nerves.
  Until recently, the quality from mobile recordings would not be good enough - but, in my day job as a journalist, I have used the technique when we have not been able to get an interviewee to a studio.
  The technology has improved massively in recent years and is often comparable to a traditional recording.
  As the process started, there were anxious days when nothing arrived, and, then, suddenly - a brilliant anecdote. (Caroline's wedding gets derailed spectacularlyâ€¦)
  I would refresh the inbox open-mouthed at relationship stories that could not be broadcast; weeding out information about people's exes that could get me sued, and in one instance, deciding against broadcasting an entertaining but detailed account of what happens when you get dysentery on honeymoon.
  The other factor that gave me a few worries was that people seemed particularly keen to share their disasters - marital break-up, hated exes, a ruined wedding, loneliness, a complete inability to pull - was there anyone with a nice, romantic story?
  It turned out there was, and it was from a woman called Samantha.
  Her tale finishes the programme, and it is a bit of a jaw-dropper.
  I knew I had something when I played it to a reasonably hard-bitten reporter at the next desk and she cried.
  One of the key decisions about the programme was that if we were handing over half an hour to Radio 4's listeners, we should go the whole hog and  get one of them to present it.
  So a few weeks ago, I emailed Narelle Lancaster.
  The 39-year-old advertising lecturer had sent in one of my favourite stories about a catastrophic night out.
  Her date's opening gambit was: "Your breasts look fantastic in that dress." And then it got worse.
  When I contacted her about presenting the programme, Lancaster, who lives in the UK, had gone back to Australia for two months.
  After realising every one of my phone recording sessions with her would have to take place not far off 00:00 GMT, I banged my head on the desk a few times and got on with it.
  Soon enough, Lancaster was sitting on the other side of the world with two phones in her hands, one landline against her ear so I could coach her, and a smartphone to record the script with in the other hand.
  She told me: "It was not easy - we did spend hours working it out, so recording a script was much more complicated than I thought it would be - lots of techniques to make you sound natural.
  "It's been incredibly exciting.
  "I only submitted because saw it on Twitter, and I really didn't think anyone would be interested in my story - I was really surprised.
  "Now, I just want to hear it."
  And now, it is time for the listeners to decide if they like the sound of themselves.
  Reaction Time can be heard on Radio 4 at 1130 GMT on 11 February.
target: When Narelle Lancaster emailed a new BBC Radio 4 programme, she did not expect to become its presenter.