Director Ken Loach condemned the Government as he accepted his Bafta award for outstanding British film.
The director of I, Daniel Blake, took to the stage to collect the first gong of the night and immediately apologised for giving a "political" speech so early on in the evening.
The film - an unflinching examination of life in the UK benefits system - beat other titles such as Denial, Notes On Blindess and the JK Rowling-penned Fantastic Beasts and Where To Find Them.
It was set and shot in the North East, with MH Southern timber yard in Jarrow used among the backdrop for scenes.
It also featured locals who scooped parts without any previous acting experience after auditions were opened up.
Loach told the awards audience: "Thank you to the academy for endorsing the truths of what the film says, which hundreds and thousands of people in this country know, the most vulnerable and poorest are treated by the Government with a callous brutality that is disgraceful, a brutality that extends to keeping out refugee children we promised to help and that's a disgrace too.
"Films can do many things, they can entertain, terrify, they can make us laugh and tell us something about the real world we live in - sorry it's early for a political speech - and in that real world it's getting darker and in the struggle that is coming between rich and poor and the wealthy and the privileged and the big corporations and politicians who speak for them.
"The rest of us on the other side - film makers know which side they are on and despite the glitz and glamour of occasions like this, we are with the people.
"Thanks for this."
Earlier, the director told Press Association that anybody "thinking of deserting the left and moving to the right" should sit down and watch I, Daniel Blake.
He said the film brings home to viewers that there are thousands of people in the situation that his characters are in.
He said: "That is, that their lives are turned into chaos when their income is stopped and this is a conscious cruelty by this government.
"They know the brutality they are inflicting and it is a disgrace that they are still there."
He continued: "Anybody who would think of voting Labour but then changes to Ukip should really look at this because if Ukip and the far right get in this will get worse."
Loach's film is going through the awards season alongside lighter films such as musical La La Land.
But the film-maker, 80, said cinema should be diverse.
"It should be as broad as a library," he said. "The sad thing is that cinema isn't diverse enough."
On bringing politics to the Bafta stage, Loach said: "It's an obligation, you can't do a film like this and talk showbiz, it's the real lives for hundreds of thousands of people.
"When you see the reality, you can't accept we can treat people like this. You see their lives in chaos, desperate for food. Cinema can do this. It can do all the ritzy glitzy stuff but it can do this as well.
"The reality is the penny has to drop, they know exactly what is going on and diseases like scurvy are coming back, they just don't give a toss.
"We have a moral obligation to get rid of them."