We are steaming through the countryside on the Keighley & Worth Valley Railway and I keep whispering: “There are German spies all over this train,” in a clipped, Home Counties accent.

I am finding this hiliarious, as is our son Charlie. My wife Claire and daughter Alice, perhaps not so much. But this creaky old carriage and the billowing plumes of white steam flowing past the window put me in mind of an old black-and-white movie, perhaps Strangers On A Train or The 39 Steps.

It is the culmination of a nice day out right on our doorstep. We have also visited the Bronte Parsonage as part of our day in Haworth, the first time with the children. And they really seemed to enjoy it.

It kicks off a rather literary week, because as I write this it is World Book Day, and the children have gone to school dressed as fictional characters.

Alice, who is whistling through a book called Norton The Loveable Cat Who Travelled The World, has gone as a cat.

Charlie has hit the age where he is less enamoured by dressing up. It must be a boy thing; I spoke to a mum at the schoolgates whose son had gone dressed as the main character from the Diary Of A Wimpy Kid books. Unfortunately, when his mum told people he was a Wimpy Kid, he (perhaps quite naturally) took the hump.

However, a trawl through the wardrobe has come up with just enough stuff to put together a passable Frankenstein’s Monster outfit, using the face-paints left over from Halloween to give Charlie’s visage a greenish tinge, and a filched eyeliner pencil from Claire’s make-up to draw some scars across his forehead.

He looks pretty good, even if I say so myself, but he worries he will look silly. I run over the story of Frankenstein again, as we’d talked about on the way home from football the night before.

“Can you remember who wrote Frankenstein?” I ask. We’d also talked about the fateful night at the Villa Diodati on Lake Geneva where the famous story was born.

“Mary Kelly,” he says. “Kelly Shelley? Mary Shelley!”

Alice is up to chapter 12 of Norton The Loveable Cat Who Travelled The World. She’s galloping on with her reading; Charlie loves stories, but seems a little more reluctant.

However, the visit to the Parsonage seems to have fired their imaginations, somewhat, even if – like Mary Shelley’s name – not all the details have sunk in properly.

“What was your favourite bit of visiting Haworth?” we ask.

“The Parsnip,” says Charlie. Which, while not correct, is pretty funny.

“And,” he says, “Seeing the sofa where Emily Bronte died while she was watching television.”

Again, not strictly 100 per cent factually correct, but close enough. And stories do get better the more you tell them, don't they?