Derek, your comedy drama set in an old people’s home, has returned for a full series. You’ve said before that you love Derek "more than any other character" you’ve created. Why?

I don’t just mean I love the character like I’d love playing James Bond. I mean that if Derek was real, I would love him as a person. He gets to me. I could well up thinking about how sweet he is. He’s us before we get burdened by what other people think of us. He doesn’t have to second guess what the right thing is: he does it intuitively. He has no burden of duty other than asking: "What can I do that will make this person feel better?"

So it’s not a traditional sitcom then…

I’ve left behind the veil of irony. This is more sincere, more straight down the line. The characters are exactly what you think they are, which makes it more dramatic because it’s a show about kindness. I think our elderly are forgotten sometimes. I’ve made the home the sweetest, nicest place to be because I didn’t want it to be a political swipe. It’s nothing to do with "care" or "care in the community" – it’s a backdrop rather like selling paper was the backdrop to The Office. But that was about turning 30. This is about turning 80.

As a society, do we have a problem engaging with the elderly?

Yes, no one cares. There are no Hollywood stars speaking out for the elderly. They’re forgotten, bewildered, and I don’t think it’s because people are cruel or don’t care. It’s because you don’t want to think about your own mortality. I think people don’t talk about it enough. There’s a strange arrogance. Sometimes being old is used as an insult, which is bizarre because, if you’re lucky, that’s literally going to happen to you. It’s a strange thing to gloat about: being born recently.

You had older parents, didn’t you?

Yeah, my brother and sisters are 65, 64, 63. I remember asking my mum when I was 13: "Why are they so much older?" She didn’t miss a beat. She said: "Cos you were the mistake." I just laughed.

Do you want to be more like Derek yourself?

Without doubt. I wish I was brave and unselfish enough to be like Derek all the time. You try to do your bit but then things get in the way; it’s a bit like the age of innocence has gone. I said I’d never say this in an interview but he’s sort of Christ-like, you know? Or what Christians should aim at being. Derek’s a religion.

You’ve explored your atheism in previous work – most notably in The Invention of Lying, a film you wrote, directed and starred in. You seem to like coming back to the theme…

Yes, because I don’t believe there is a God but there’s nothing wrong with spirituality if that makes you a happier, nicer person. But religion is something else, it’s a way of controlling people. It’s no coincidence that the people in charge of religion aren’t the kindest or most forgiving. My point is that… you don’t need whatever religion gives you. Just be kind.

With The Office and Extras, you satirised celebrity culture and the desire people have to be famous. Have you moved on from that now?

Definitely. Ten years is a long time to be doing that. It is irresistible to do what you know… For the past 10 years, I’ve been in media… This [Derek] is a return to before that. It’s about normal people with real issues and there’s not a hint of glamour or the quest for fame.

But there’s a scene in the new series where a care home assistant admits she looks up to the Kardashians and only reads Twitter, so you’re still satirising it a bit…

We’re all guilty of that. People might think that’s me having a go at the uneducated youth but it’s not really. I’m having a go at how we care for people growing up. This woman is like she is because she’s never had any love. The first time someone shows her a little bit of love, she cries. Kindness trumps all.

Have you met the Kardashians?

[Laughs] I haven’t, no.

You’ve hosted the Golden Globes three times and got a lot of media attention for your close-to-the-knuckle jokes (introducing Bruce Willis on stage as "Ashton Kutcher’s dad" and claiming you’d seen Colin Firth "punch a little blind kitten"). Were you ever nervous about saying these things?

No. The adrenaline rush I get could be construed as nerves but I know it’s not: it’s excitement to see how this goes down. I think all art – even one as lowly as making jokes about celebrities – is there to make a connection. I tweet because I want to know what people think [of my material]…

There are loads of reasons I did the Golden Globes. I wanted to write some gags because I don’t usually do many gags. It was an amazing opportunity – it’s seen by 200 million people worldwide. There’s not a comedian around that would turn that down. And that was fun. The reason I did it again was because I thought I could improve. The reason I did it a third time is because the press said I’d never be invited back.

Who is the most impressive celebrity you’ve ever met?

Christopher Guest, no doubt. He’s always been a hero of mine, my biggest influence, and he’s become a friend, a mentor. He’s the sanest, nicest, most beautiful, rational man in the world, a man of pure integrity – and that’s hard. It’s hard to find.

You’ve been accused of poking fun at learning disabilities (Derek), dwarfism (Life’s Too Short) and various other things. Are we too quick to take offence?

Anything you say will offend someone. We’ve been sold this myth that if you’re offended, you’re in the right. Most people are offended because they think they should be or because they mistake the target of the joke with the subject of the joke. I understand nobody deserves to be persecuted or ridiculed because of something they can’t help. But I am allowed to ridicule someone who believes the Earth is 5,000 years old or a gay child will go to hell.

Your girlfriend, Jane Fallon, is a novelist. Do you get each other’s opinions on your writing?

We discuss everything, even if it’s a puppy we saw that day… We’ve just got so much in common. I think if you’re together after 30 years, something must be right. Umm, I do run things past Jane? Usually, I come back from a run and say, "What do you think of this?", and she’ll say, "Please don’t do that in public". But I don’t read novels. I’ve only read one book, when I was 28, and that was The Catcher in the Rye, and I’ve got to read another one [before I read hers] because she said "I’m not allowing my book to be the next one you read after The Catcher in the Rye". I feel terrible about it but I just don’t read books. I’m going to do that when there’s nothing else to do and I’m 70 and lying on a beach.

Derek is on Channel 4 on Wednesdays at 10pm