Up-and-coming actress Molly Windsor has beaten Hollywood heavyweights Claire Foy and Thandie Newton for the leading actress prize at the TV Baftas.
Windsor (20) triumphed for her role in Three Girls, a drama about the Rochdale child sex abuse scandal, which also won the best mini-series prize at the ceremony.
It told the harrowing story of the children who were groomed, sexually abused and trafficked by British Pakistani men in Rochdale.
Foy had been nominated for a second consecutive year for her role as the Queen in The Crown, while Newton was nominated for Line Of Duty.
Also in the running in the category was Sinead Keenan, who received a nod for playing the mother of Rhys Jones in Little Boy Blue.
Collecting the prize from Sherlock star Martin Freeman, Windsor said: "Three Girls was born out of the courage of the real three girls, and the real Holly, Amber and Ruby, who told their story over and over and over and told it again to us.
"I just want to say thank you for recognising how selfless that is and how brave that is."
Foy's co-star Vanessa Kirby triumphed in the supporting actress category for her portrayal of Princess Margaret, giving streaming service Netflix its first TV Bafta.
It picked up its first film Bafta for Ava DuVernay's documentary 13th in 2017.
BBC Three comedy This Country picked up two gongs at the ceremony, with star Daisy May Cooper landing the female performance in a comedy programme prize, while the show won the scripted comedy award.
ITV2 dating show Love Island scored a Bafta in the reality and constructed factual category but it was defeated by Blue Planet II for the Virgin TV must-see moment prize.
The scene of a mother pilot whale grieving her young scored the only prize voted for by the public.
Former footballer Rio Ferdinand's programme Rio Ferdinand: Being Mum And Dad, about the loss of his wife Rebecca to cancer, won the single documentary Bafta.
He described the documentary as a "snapshot of that time of sadness", but said it has helped him heal.
Peaky Blinders was winner of the drama series category, while Murder In Successville won the Bafta for comedy entertainment programme.
Britain's Got Talent won entertainment programme and Casualty was named best soap and continuing drama.