Bent, at the intimate Tabard Theatre in Parsons Green, west London, is an immensely moving, thought-provoking and engaging piece of theatre.

With a young Sir Ian McKellen taking the lead of Max, the play took London by storm in its original run in 1979. Set in decadent 1930s Berlin, we meet Max (Russell Morton) and partner Rudy (Steven Butler). The pair witness the murder of a German SA officer who they slept with the night before and their world soon becomes chaotic as they try to escape persecution by going on the run.

They’re eventually captured and sent to the infamous concentration camp Dachau. What follows is an often heart-breaking, brutal and passionate story of love and survival, a story of what happens when someone’s humanity is pushed to the edge.

It had critical acclaim then, and it deserves the same now. Bent opens on a scene many of us can relate to – a pair of young men chatting about the events of the night before. Such natural dialogue flows between Max and Butler’s immensely likeable and down-trodden Rudy, that they could be talking about a recent night out in Soho or Vauxhall rather than 1930s Berlin.

The similarities between the gay scene in London now, and Berlin then, are plain. Drugs, alcohol and hedonism feature in both. However, our current reality and the reality back then – with the terror of the Nazi regime that is about to unfold – could not be more different, making Bent more powerful still.

Russell Morton’s portrayal of Max is gripping from start to finish. His character is loving, selfish, idealistic, witty and damaged all at the same time. His personal and emotional journey will make you laugh and cry as he hurtles towards the cover-your-eyes climax of the play.

All the cast of Bent deserve a great deal of credit. It’s a true pleasure to see such natural, youthful acting – zooming from high-camp gags to the darkest corners of human nature at lightning speed.

There are some very bleak moments, punctuated by great sparks of hope and light in the most hopeless of situations. It’s a tumultuous ride, but also a warming testament to the strength and power of the human spirit.