The co-star of the serial killer drama reveals five secrets from the set

1 I play Angela, the wife of Dutch diplomat Herman Knippenberg, who sought to bring to justice Charles Sobhraj after he killed travellers on the ‘hippie trail’ through Asia in the 1970s. I spent time with the real Angela – the conversations we had and the pictures she sent me from that time really helped with my portrayal.

2 Filming in Bangkok was extraordinary. It’s a fascinating place and provides an incredible backdrop to much of our story. And the food provided by the caterers in Thailand was amazing! It was wonderfully spicy and they kept coming up with more delicious and surprising dishes.

3 One of the trickiest parts of the job was learning the sections of the script that were in Thai, a language that, with its rising and falling tones, is very different to

English. I was fortunate enough to have a really good Thai teacher, and I found the best way to learn the words was to turn them into a kind of song which I walked around my hotel room singing! Weird, but it worked.

4 We filmed during the rainy season in Thailand and this certainly caused some challenges. The intensity of the rain meant one particular scene had to be postponed four times before it was finally completed.

5 We got to within eight days of finishing the shoot in Bangkok before we had to suspend filming in March because of Covid-19. We finally got working again in August, but in Tring, Hertfordshire, which, because of travel restrictions, stood in for Bangkok and parts of India and France.

Ellie as Angela with Billy Howle as Herman