Marc Fennell

And so with shaking hands, he taps out a telegram.

As the man makes his way to London, this message races alongside him to actually beat him there.

So the train journey takes about an hour, which sounds like plenty of time for this information to get to Paddington.

Because I think when we imagine a message travelling through an electronic wire, I think we kind of imagine it being instantaneous.

The thing is, with telegraph technology, it was certainly fast, but the message itself took longer because, remember, it has to be transmitted, but then it also has to be received.

So transmitting three letters per minute, which is not exactly speedy.

But then once the message is received, it has to be deciphered, which again takes even more time.

So not only has Slough sent through a very long message, they've also sent it through with typos because apparently the model of telegram machine at the Slough station was not great.

In the message, Quaker is spelt with a K and the word just is spelt with a G. Anyway, it's safe to say that the team at Paddington have their work cut out for them and receiving, and I suppose more importantly, understanding the message from Slough.

While all this is happening though, that man is sitting comfortably on the train, watching the scenery outside, completely unaware of the urgent tapping and deciphering happening.

But who exactly was he?

And why would he want to poison Sarah Hart?

Yes, as was the norm at the time, England sent its criminals and crooks to the Antipodes, landing them down under to start brand new lives, as was the case for John, and family life as well.

Then in 1831, John and his family are back in London.

And it doesn't take long for the noisy, crowded, dirty city to take its toll.

Within a few years, John's sons get sick and die.

And then his wife falls ill as well.

John needs help looking after her, so he hires a nurse.

A nurse with the name Sarah Hart.

That affair leads to two more children.