David Harewood: I had a shocker on the set of The Night Manager

Two days earlier, he tweeted: “Between me and you, I think I must have dropped my talent on plane over here cos I've had a shocking start.”

Then: “If I'd have been a footballer today there is no doubt I would have been dragged off after 20 minutes. I had an absolute shocker.”

So what happened?

“Well I’d been working in America – until 4am on Friday, then 3am on Saturday – then I flew here and went straight on set. I hadn’t seen my kids four months and I was jetlagged. And I was just not mentally there. I couldn’t remember my lines, I couldn’t focus. Literally, I was sweating.”

The really surprising thing is that you’re prepared to reveal this to your 30,000 followers on Twitter?

“We all have bad days. I think it’s quite interesting that some actors don’t want to talk about that.” Failure, he says, is not “the opposite of success, it’s an integral part of success.”

And how’s filming now that the jet lag has lifted and you’ve seen your daughters (Maize, 12, and Raven, 10)? “I’m absolutely loving it.”

So who is Joel Steadman, Harewood’s character in The Night Manager? Harewood doesn’t want to spoil the plot, beyond saying that he “works in the spy game and travels the world trying to put away people who are trading in weapons”. But he’s very different from Harewood’s role in Homeland, “who never smiled once in the two seasons I played him.”

These days, Harewood splits his days between LA – where his career is booming – and London. The boy from working-class Brum has done well for himself. So well, in fact, that his former comprehensive school, now the Washwood Heath Academy, has named one of its houses after its star pupil (“Harewood House”, not to be confused with the stately home in Yorkshire).

Yet, he fears acting is becoming more difficult for people from his background.

Look around The Night Manager: the two main stars, Hugh Laurie and Tom Hiddleston, both went to Eton (and John le Carre taught there!). And Damian Lewis, who starred with Harewood in Homeland, also went to Eton.

Does he feel like he’s surrounded by Old Etonians? “Chased by Etonians? Yeah. Well, the world is chased by Etonians!”

Harewood, who went from his comprehensive straight to Rada, says: “There’s no way in the world I would be able to go to drama school now. I got a grant from Birmingham Council – I auditioned behind somebody playing the spoons – but that whole system is gone now. So I think it would be very hard for a young black kid from Smallheath in Birmingham to get to Rada.

“I’ve got no problem with the public school boys getting through – but it’s a shame that now the majority of those coming through are guys who have had that helping hand. That’s not to say they’re not talented – they’re extremely talented all of them – but whether or not a young kid in my position could get there now, I’m not so sure.”