How meeting Mike Leigh raised Sally Hawkins' game

For Sally Hawkins, a role in Mike Leigh's first feel good comedy was a serious education. By Stephen Applebaum

When Sally Hawkins won the Silver Bear at this year's Berlin Film Festival for best actress in Mike Leigh's Happy-Go-Lucky, it was a triumph not only for the engaging 31-year-old south Londoner, but also for positivity. While other directors at the annual festival traded in misery and pessimism, Leigh and Hawkins mined a sunnier seam of warm-hearted laughter and optimism.

Leigh's first feel-good comedy, the film surfs on a wave of good cheer, supplied mainly by Hawkins's charming and subtly drawn portrayal of a north London primary school teacher, Poppy, who meets the world with a smile and a generous spirit that not even Scott (Eddie Marsan), her racist driving instructor, can dampen.

A familiar face from television dramas, such as the adaptations of Sarah Waters's period lesbian novels Tipping the Velvet and Fingersmith, as well as a recurring role as the girlfriend of Little Britain hypnotist Kenny Craig (Matt Lucas), it was Hawkins's own personality that inspired Leigh to want to collaborate with her, following her smaller roles in his previous two films.

"Apart from being very creative and intelligent and good to work with, and all those things," Leigh gushes, "she has this kind of openness and humorous-but-serious take on things. She played very different characters in Vera Drake and All or Nothing. So I just felt yeah, we could make a character who was multi-faceted and complex, but energetic in some way."

It is easy to see why he was charmed by Hawkins. Like Poppy, she exudes positive energy and a zest for life, though thankfully not the character's taste in gaudy clothes – the kind that stop traffic for all the wrong reasons.

"Where we're similar is I'm naturally smiley and optimistic, and I love humour," she says. "The reason I got into acting is I love comedy. What was fun is having that space to be quite cheeky and mischievous and naughty, and to laugh openly and not care."

Unlike Poppy, Hawkins says she normally tends to over-analyse things. "I'm a perfectionist. I worry myself to bits. But what I learnt from her is her ability to sail through life and let it go, and not give myself a hard time. I think that's fantastic!"

Although she was aware that Leigh was using her a lot in the film, Hawkins says you can never take anything for granted when you work with the veteran auteur. "You have to go into a Mike Leigh film like, 'I don't know what I'm doing, I don't know where I will end up, what I'm playing, what film we're making, or if I will end up on the cutting-room floor at the end of it.'" It is an act of faith, and Leigh tells of actors who have turned him down because they do not want to take that step. He demands total commitment, and his actors are not allowed to work on anything else while they work with him. Not that Hawkins would have wanted to. Leigh's method of creating characters and scenes and dialogue through improvisation over months requires absolute concentration.

"All your time is given over to him and the part and creating this world," says Hawkins. "You'd go insane trying to keep other worlds in your head."

Numerous actors have attested to the challenging and exhausting nature of Leigh's process, but Hawkins says she has grown through the experience. "He instils in you a discipline and a focus. He asks you to use your brain." She chuckles conspiratorially. "If actors can get away with the bare minimum, they will. I'd not known any other way. You think you're doing good work and then you meet Mike, and you think, 'OK, I've got to step up my game.' I hadn't even been scratching the surface."

The irony of Hawkins's performance is that all the hard work is subsumed within a character who dances through life, though she can be serious when required. The intensity of the work and Leigh's demands were offset, to some extent, by the joy of being in Poppy's skin. Apologising for risking sounding corny, it was a "lovely feeling", enthuses Hawkins. "It was like riding this bubble of excitement. For me, she's like on the edge of a giggle all the time. And if that wasn't there, it wasn't connected to Poppy. It's like when you're a child and you're told to be quiet and you're holding in laughter. She's that for me."

Hawkins says that as far back as she can remember she has enjoyed making other people laugh. She "fell into acting" because she loved improvising sketches and working with her mates during lunch hour at school, creating "mini-playlets" to make their friends laugh. "I loved the buzz of that," she says excitedly. "And I still do."

The actress grew up in Greenwich and Blackheath, south-east London, with parents Colin and Jacqui, who are successful children's authors. Their daughter has written comedy sketches, but baulks when I bring this up. "Um, well, yeah, but I hate saying that to writers," she says, embarrassed. "I have written sketches and, recording them with a live audience, you think, 'My God, I've written these words and they're having an effect on people.' There's nothing greater than that."

Her parents started to write to encourage Hawkins to read, because she was still having difficulty when she was five. And, although it is hard to believe today, watching her garrulous, quick-witted performance in Happy-Go-Lucky, she did not speak until she was nearly three.

She cites Peter Sellers as a "huge influence". "He was a great comedian because he's a fantastic actor, and his life is so funny because it's so difficult. You've got this dual thing going on, and the darkest moments are the ones that can be the funniest."

Her work has switched between light and dark. Before Happy-Go-Lucky, she worked on Woody Allen's new tragic-comedy, Cassandra's Dream, with Ewan McGregor and Colin Farrell, and on Tom Shankland's gruesome serial killer thriller Waz, starring Stellan Skarsgard.

"That was certainly an experience. It was such an extreme character, incredibly dark. She was tough to play because she had been so damaged by drugs, and was incredibly self-destructive." Luckily, working with Leigh on All or Nothing had taught her how to detach herself from a character, so she was able to rid herself of the effects quite quickly.

"He demands that you step in and out of your character, and refer to your character in the third person," she explains. "I think it's very good, because that's you and that's your character, and you can leave them at the door and go home."

Hawkins says she would like to revisit Poppy to see where life takes her. Leigh, however, is adamant that this is Poppy's one and only appearance. Life is too short, and money in too short supply, to return to characters, he says drily. Meanwhile, Hawkins has moved on to Lone Scherfig's Nick Hornby-scripted movie, An Education. Would she work with Leigh again if called? Of course, she exclaims.

"If you're lucky enough to be asked to be in a Mike Leigh film, you don't turn it down."

Happy-Go-Lucky is released on 18 April