The husband and I walked 20 kilometres around London on Saturday – just for fun.

I have a bit of an obsession with walking around cities. When I lived in London, I would wander around the streets for hours on my own like a vagabond, peering at unusual buildings and discovering new thoroughfares; I would set myself strange little challenges to get to places purely on foot.

The husband is less enthused about trekking for miles for no apparent reason. But over time, he’s begrudgingly become an hiking urbanite too.

On Friday, we walked to the Natural History Museum to see the Wildlife Photographer Of The Year Exhibition. (If you haven’t been, it’s ace. The images are awesome but you have to be quick: it ends this month.)

And then, during a wander through the tawdry tourist-trap of Leicester Square, our eyes fell upon this:

It was an advert for a play called Ghost Stories, with the tagline ‘You haven’t seen horror until you’ve seen it live’.

Have you ever seen two people look more fearful? Take a closer look.

The husband and I became a little obsessed by The Faces Of Fear (their terrified expressions were also plastered all over the tube too). So obsessed, in fact, that we woke up on Saturday morning and decided we wanted to see Ghost Stories ourselves, simply to see just how scary/ naff it actually was.

I tell a lie: the husband really wanted to see The Book Of Mormon, which by all accounts is one of the best West End shows in recent years. It’s also sold out weeks in advance. But every day at 2pm (and again at 5pm) they do a raffle draw for 20 random people to be offered spare seats for a bargainous £20.

Entering the raffle is quite a lot of fun in itself. You have to head down to the theatre in person, fill out an entry form and pop it into a giant tombola, while a slightly irritating thespian type bellows jokes to the assembled throng through a megaphone.

At 2.30pm, the theatrical joker started pulling names out of the tombola machine, with dramatic fanfare. As the names started being called out, a little part of me secretly hoped that we wouldn’t be chosen (after all the hype, I kind of had my heart set on Ghost Stories).

Looking at the hopeful faces of the crowd around me, I even started dreaming up a scenario whereby if our names were drawn I would rather grandly announce, ‘Of course, I’m pleased that I’ve just won two tickets to the hottest West End show of the year.

‘However, there’s a little play down the road called Ghost Stories that we simply can’t miss. Here, have my tickets.’

I started scanning the flock of people trying to identify who was most deserving of this over-blown gesture. I settled on two little old ladies, waiting patiently at the edge of the crowd.

Our names never got called.

At 5pm, we found ourselves crammed into rickety chairs at the edge of the stage in the ramshackle Prince of Wales theatre, awaiting the curtain call for Ghost Stories. These are the kind of seats you get lumbered with when you pay £20 for a last-minute ticket. Spooky music was wailing from the speakers; a sense of anticipation filled the air.

We even attempted to recreate The Faces of Fear for ourselves.

There was a warning sign stating that anyone with a nervous disposition should leave now. As the lights darkened, I started to feel a bit nervous. Just how terrifying was this spectacle going to be? Could my heart (which has recently become prone to palpitations after too much coffee) even take it?

Turns out, I shouldn’t have been worried.

It was dire.

Heard the story about the man who is driving through some woods when a ghostly figure suddenly runs out in front of his car? A few miles down the road, his car predictably breaks down, leaving him stranded with only a ghoulish figure for company who starts ominously tapping on the roof of his car.

Let’s just say this story is best left for round the camp fire: trying to recreate it on stage ends up being rather comical.

More silly stories ensued: the security guard who was on a night shift at an empty warehouse. After lots of creeping around and banging of doors, he then gets attacked by a… mannequin! Yes, one of those waxy shop window dummies suddenly comes alive and grabs him at the throat. Cue shrieks from the audience and chortles from the husband.

Jonathan Ross was clearly on drugs when described it as ‘awesome, scary fun’.

There was, inevitably, a weird twist at the end. At this point, I feel I should honour the old West End etiquette: that one should not give away the ending to other potential theatre-goers.

But let’s just there’s a reason why I tell my pupils never to end a story with: ‘It was all a dream.’

After Ghost Stories, we decided to work up an appetite with a three-mile stroll to Mayfair. What I love about London is you can just roam for miles, before stumbling into a darkened bistro to gorge on a three-course feast. Following this gluttonous binge, the husband suggested that we might get a cab back to the hotel.

‘A cab?!’ I said, incredulously. ‘But it’s a mere 2.5 miles back to the hotel.’

The husband sighed. And off we went again.

We strolled back through Mayfair; we sauntered across Trafalgar Square, saluting the Boris’s Big Blue Cock as we passed.

Finally, at the end of Fleet Street, the ghostly silhouette of St Paul’s loomed into view.

Back at the hotel, the husband declared himself so worn out that he could barely brush his teeth. I, meanwhile. eagerly checked my Jawbone UP band.

28,000 steps and 20 kilometres!

I went to bed very happy.

And then had a nightmare that I was attacked.

By a ghoulish mannequin.