Chi-Raq is about women in South Chicago who decide to withhold sex from their men to get them to stop killing each other. The story comes from ancient mythology, namely Lysistrata by Aristophanes. "It was originally [cowriter] Kevin Willmott's idea," Lee says. "He wrote the first treatment. We tried to get that off the ground but couldn't get it done. So a year ago I gave him a call and I asked if he still owned that script. He told me yes, it's still free. So I said lets cowrite it and let's make it take place in the South Side of Chicago. And here we are now. But it wasn't easy."

Spike Lee at the premiere of Chi-raq

Finding a studio to finance the film was the next big challenge. "Amazon was the one who said yes. Everyone else said no," he says. "And I understand their hesitation a bit because the entire script is written in verse!" Lee has been outspoken about race and violence in America throughout his career, which has spanned such classics as 1989's Do the Right Thing, the biopic Malcolm X and the heist thriller Inside Man. So he wasn't surprised when Chi-Raq's trailer sparked an explosion of criticism on the internet.

"I know people in Chicago are sensitive about this, but the truth is the truth: Chicago is the murder capital of the United States of America. New York City has three times the population, yet Chicago has more homicides than New York. That's not me saying it, that's the truth. And if you don't like the numbers, do something to change it."

Recently, Lee was given a special Oscar, using his acceptance speech to remind studios that the industry has a long way to go racially. "I didn't say this to be mean," he says. "I just think sometimes white folks don't even know that is even something to consider. It doesn't even occur that there are no people of colour in any positions of power in these studios or networks. So I had to bring that up. But to have Denzel Washington, Samuel L Jackson, Wesley Snipes - brothers who I dearly love, brothers who I've had in many of my films - present me my Oscar, I mean, wow!"

Watch the trailer for Chi-raq here: