Few songs arrive accompanied by a statement of intent, but Ben Drew believes his latest single requires clarification. Its subject is the riots that erupted across England last summer. The news, says Drew, moved on so fast – from street fights in Tottenham to the battle for Tripoli – that they were never properly examined. And as the 28-year-old songwriter, singer, rapper, film-maker and actor better known as Plan B explains on his website: "The point being made in my song 'Ill Manors' is that society needs to take some responsibility for the cause of these riots. Why are there so many kids in this country that don't feel they have a future, or care about having a criminal record?"

Drew posits at least one theory himself: that underprivileged young people, living on urban estates, suspect society doesn't much care about them – and thus care little for society. They're casually branded "chavs: council housed and violent", a term no better in Drew's eyes than those used to discriminate along racial and gender lines. "If you're born into a family that has enough money to educate you properly," he goes on, "you are privileged. You're not better than anyone else. You're just lucky. Certain sectors of middle England, not all of them, but the ignorant ones, need to wake up and realise that... and stop ridiculing the poor and less fortunate. That is what this song is about."

Already, the right people are beginning to take notice. After it was posted on YouTube a week ago, Labour's shadow health minister, Jamie Reed, tweeted that "Ill Manors", in substance if not in style, reminded him of Marvin Gaye's "What's Going On". "The risk of any lefty politician being pilloried for praising the new Plan B track is really pretty high," Reed admitted. "That said, it's excellent." In a blog, music writer Dorian Lynskey called it "the first great mainstream protest song in years", comparing it to Public Enemy and The Clash.

Effective protest songs are rare nowadays, the form weighed down with cynicism. But on "Ill Manors", Drew swerves the clichés. His shouted chorus is confrontational: "Oi! I said Oi! What you looking at, you little rich boy?" Yet the rapped verses – strapped to a thrilling, Prodigy-like track – are witty and complex: "We got an eco-friendly government/ They preserve our natural habitat/ Built an entire Olympic village/ around where we live, without pulling down any flats." Integral to its impact is the video by Yann Demange, director of the recent Channel 4 drama Top Boy. Demange's promo is laced with real footage from the riots, and expressly designed to be discomfiting to Disgusted of Tunbridge Wells.

"I'm not trying to condone what happened during the riots," Drew told BBC 1Xtra DJ MistaJam in an interview. "It disgusted me... it saddened me more than anything, because those kids who were rioting and looting have just made life 10 times harder for themselves. They've just played into the hands of what certain sectors of middle England think about them." The single is just the first part of a bigger plan for tackling that mindset; in May, Drew is releasing a feature film, which he wrote, directed and soundtracked. Ill Manors is a "hip-hop musical" made up of six intersecting east London stories, starring Riz Ahmed and Natalie Press.

All this may come as a shock to those who first encountered Drew on his previous LP. The Defamation of Strickland Banks (2010) was an accomplished Motown pastiche, a coffee-tablish concept album about a sharp-suited soul singer locked up for a crime he didn't commit. To those who were fans of his 2006 debut, however, it's a welcome return to hip-hop. Who Needs Actions When You Got Words was released mere days after David Cameron, then the leader of the opposition, became the latest politician to condemn hip-hop for encouraging violence. Drew's first album gave the lie to such claims, with its nuanced first-person portrayals of street crime, poverty, addiction and underage sex.

When Drew turned his back on such things, Sam Wolfson, reviewing Strickland Banks in the NME, expressed disappointment. Now, however, he sees brilliance in the decision. "Lots of people who'd want to do something like 'Ill Manors' just don't have the profile in middle England that Plan B does," says Wolfson. "Strickland Banks was hugely successful with a super-mainstream, Radio 2 crowd. To most people, he was a bad-boy-done-good soul singer, not all that dissimilar to an X Factor contestant. That makes the force of this single so much greater, because it comes from such a mainstream place."

Drew was born in 1983 and brought up in Forest Gate, east London, where Ill Manors is set. His father, Paul Ballance, a former punk musician, left home when Drew was five months old, and dropped out of the boy's life altogether when he was six. He sent his son a congratulatory text when Strickland Banks went to No 1, but Drew deleted it and the two haven't spoken since. His mother, "a saint", was a local-authority architect. "We weren't working class but we weren't middle class," Drew has said. "We were in the void in between."

As a young teenager, Drew taught himself guitar, aping Britpop acts and penning romantic soul numbers. Only later did he take up rapping, his "Plan B" shifting his songwriting focus to his mother's unsuitable boyfriends, his father's failings, his tough school life. He was expelled for fighting more than once. He threw chairs and verbally abused his teachers, and at 15 was sent to the pupil referral unit that he later claimed had turned his life around. He regressed once, in 2007, when he received a suspended sentence for threatening a stranger, kicking a bin and swearing at police. He subsequently spent time in therapy and swore off drugs.

Who Needs Actions was not a huge hit, reaching a modest No 30 in the charts despite its five-star reviews. But Strickland Banks went triple platinum, winning Drew three Ivor Novello awards and a Brit for Best British Male. His inadvertently prescient performance at the 2011 Brits ceremony featured a staged prison riot. Musical success also helped him to develop an acting career, with roles in Adulthood (2008), Harry Brown (2009) and 4.3.2.1 (2010). This year he'll star in the big-screen remake of The Sweeney alongside Ray Winstone.

Meanwhile, Drew's been trying to make a name behind the camera. A music video for electro duo Chase & Status in 2008 was followed by a grim short, Michelle, which now forms one of the narrative strands in Ill Manors. No production company was interested in funding the feature film, so he raised the budget independently, starting with £4,000 of his own savings. His favourite movie, he says, is Forrest Gump.

Assuming his latest project has the broad impact that he's aiming for, Drew has expressed a wish to establish a charity to fund and empower those individuals in troubled and underprivileged communities that he calls "vigilante social workers". There is a danger, though, says Wolfson, in holding him up as "Plan B, Voice of Britain's Feral Youth", adding: "What's been interesting about the youth resistance, with the student protest and the riots, is the total avoidance of leaders. But because there's a vacuum, there's a natural media tendency to search for some kind of spokesperson. It's that Newsnight thing of bringing Dizzee Rascal on to talk about the presidential election."

Nevertheless, Drew's ambitions are considerable. "I started to write an album that would try to reach out to these kids and, in some ways, to be a father to these kids, because they were parentless," he told a TED conference last week. And, in his 1Xtra interview, he suggested that mission was lifelong. "A lot of these kids come from family environments where they're told they're no good and will never amount to anything, and when they walk out of their front door, society tells them the same thing... But you can change that... That was the motive behind my first record, and will probably be the motive behind any hip-hop music I'm ever going to make, until we change the issue – and then I can start making pop music."

A Life In Brief

Born: Benjamin Paul Ballance-Drew, 22 October 1983, in east London.

Family: Mother worked for the local authority. Father left when Ben was five months old.

Education: Anglo-European School, Ingatestone, Essex; Tom Hood School, Leytonstone.

Career: First album in 2006: Who Needs Actions When You Got Words. First major film role in Adulthood (2008). Second album, The Defamation of Strickland Banks (2010). Directed the film Ill Manors.

He says: "If anybody wants to talk to me about how I think we can change these things I'm ready."