The difficulties of reviewing You Me Bum Bum Train have been widely discussed. Everyone who goes to the show is asked to “maintain the mystery of the journey” for the duration of its run. And yet the experiences you encounter en route are so rare and out of the ordinary, you want to shout them from the top of Centrepoint.

‘Not knowing’ is the key ingredient of this immersive theatre piece – your childish naivety what brings you on board as an active participant in this grand game of make-believe. And believe me, you’ll get as much as you give.

The ‘ride’ has changed since its last incarnation. Now installed in the cavernous Old Sorting Office building in Holborn, the wheelchair mentioned in our last review makes only one brief but powerful cameo – get ready to get down on your hands and knees this time.

Both a visual and visceral experience, it also forces you to mine the depths of your imagination, conscience and sense of identity. Not the Nancy Groves Show exactly, but passengers are as much a part of proceedings as the hundreds of volunteers involved in this (not so) word-of-mouth success.

And then, just like that, you’re plunged, blinking, back into reality. Stepping out onto dark and damp New Oxford Street, I felt elated, only to be hit by a sad realisation: that was my last first ride of the You Me Bum Bum Train – and now I’ll never ‘not know’. It felt like growing up all over again.