Ten years ago, in 2011, David Aaronovitch felt like he was losing his grip on reality. He'd been placed in a coma, after a surgery gone wrong. Now he was awake and in Intensive Care.

Every time he closed his eyes the inside of his eyelids would display a kaleidoscope of red, black and yellow violent cartoon images. Faces appeared before him like odd animation of computer game avatars. That was just the beginning. For the next four days and night David experienced what he describes as a "waking nightmare".

These types of hallucinations are called delirium and are a very common side effect of being placed in an induced coma.

Now the number of people experiencing delirium is on the rise. That's because those who are critically ill with Covid often have to be ventilated. While it helps their bodies fight the virus, and will often save their lives, the mental toll can be as serious as the physical one. Increasingly, patients are leaving hospital physically healed but mentally scarred.

In this powerful and immersive documentary David Aaronovitch hears from three people who have struggled with delirium, and shares his own experience.

Producer: Caitlin Smith Executive Producer: Peter McManus Researcher: Anna Miles Sound Design: Eloise Whitmore

With thanks to Paul Henderson, Zara Slattery, Robin Hanbury-Tenison, ICU nurse Crystal Wilson and Dr Dorothy Wade of Barking Havering and Redbridge Universities Hospital Trust and North EAst London Foundation Trust.

Image courtesy of Zara Slattery.