There is a scene in Gurinder Chadha’s new film in which a gaggle of teenage girls - they call themselves the Ace Gang - discuss the Queen’s 44DD ‘nunga-nungas’ (their euphemism). Call it prudishness, but it provoked a collective gasp in the audience at a screening last week. “That’s what girls talk about,” Chadha says, laughing, when we meet the following day. “They are obsessed with boobs at that age.” She pauses. “Maybe that was a bit below the belt, now you mention it. It’s the truth, though.” She has the bra size on good authority.

Chadha goes quiet for a bit; she’s wondering what the Queen, who awarded her an OBE last year, might think about ‘Angus, Thongs and Perfect Snogging’, the film she has adapted from Louise Rennison’s phenomenally popular teen novel. She’s pretty sure most of the Windsors saw her film ‘Bend It Like Beckham’ (well, everyone else did); Princess Anne collared her about it at a function. In the end she decides the Queen would probably quite like Angus. “It’s a lovely film about her subjects.”

If you haven’t heard of Rennison’s series of novels - you soon will. There is a marketing juggernaut behind this film. Chadha calls Georgia Nicolson, the narrator of the books and unofficial leader of the Ace Gang: “Bridget Jones at 14, but with more attitude.” Played in the film by Georgia Groome (who was the teenage runaway in Paul Andrew Williams’ ‘London to Brighton’), she is a classic teenage heroine: not necessarily the prettiest of the group, but a bit kooky, with a stock of smart and often self-deprecating one-liners. Which makes her far and away the coolest. The gang even have their own language: everything is either “beyond marvy”, or else they’re having a “nervy b” brought on by a boy or a hair-plucking catastrophe. Some of it - HRH’s assets being the most extreme - is mildly risque, but these are what Chadha calls ‘good girls’.

In truth, most parents would be delighted if their daughters were only getting up to this kind of mischief. That is Chadha’s point. She says she wants to show the lives of 99 per cent of girls who are not getting into bother, who never make it on to the news: “We might read about the 1 per cent of teenagers knifing each other, leading a violent life, but there are a vast majority up and down the country who are good girls.”

You get the feeling that Chadha was like this lot as a teenager, all about her mates and having a laugh. Was she a good girl? “Oh God, yeah,” she laughs. “Sort of.” Her family moved to London from Kenya when she was a baby, and she grew up in Southall. Now in her 40s, she is also one of this country’s most commercially successful directors. ‘Bend it Like Beckham’ made £32m at the box office and she wields enough Hollywood clout to persuade movie mogul Harvey Weinstein into making a Bollywood cameo in her last film, ‘Bride and Prejudice’ (he kept his sunglasses on, mind). After Bride she was lined up for the mega-budget remake of ‘Dallas’, which fell through when the producers learned that under-38s didn’t have the first clue about the original television show. Though the film should still appear, Chadha is no longer involved . She was pregnant when her six-month contract expired, and came home to London.

If ‘Angus’ looks like backward step after ‘Dallas’ - another small-scale Brit film - it might be worth taking a look at sales figures for Rennison’s books. They are big here but, significantly, massive in the US, where the fourth in the series, ‘Dancing in My Nuddy Pants’, was No 1 on the New York Times’ bestseller list.

But what is it that makes Chadha’s films such crowd-pleasers? Like the director, the films never take themselves that seriously, and put the emphasis on the sweet in bittersweet. Chadha’s films are always a bit raucous, too.
Clearly the most pressing question - to Georgia Nicolson fans at least - is how much Chadha has changed the book. There’s been a fair amount of tinkering to make it acceptable to younger girls, or more accurately, to make the material acceptable to their parents. The title of the book, the first in the series, ‘Angus, Thongs and Full-Frontal Snogging’, is now a less suggestive Perfect Snogging. Gone, too, are references to drugs, smoking and going all the way (not, let it be said, that the Ace Gang would ever dream of doing any of these things). If anything, Chadha has focused on the friendships, the mates-in-it-togetherness, scaling back some of the (already pretty low-level) bitchiness.

As in all her films - in which men, dads apart, can be a bit like male bimbos - it’s all about the women. The male with most screen time is probably Angus, who is a cat. I ask her if all her films are ultimately about the same thing, girl power? “Hello,” she says, arms in the air, at her most animated before finishing more seriously: “All my films are about kind of being seen to be one thing when you’re actually something else, and the power of the female spirit to make things work your way on your terms. Which is what I do.” Angus, Thongs and Perfect Snogging is released on July 25.

The Guardian