The Wire star landed the Best Actor prize for his role in U.K. series Appropriate Adult, a reconstruction of the police investigation into the notorious murderer, while his co-star Emily Watson won Best Actress for playing Janet Leach, who sat in on the interviews Fred West gave to cops.
As he collected his award, West said, "I hope she (Leach) has had some closure and I hope she feels we honoured the suffering she endured and the suffering of all of West's victims, living and dead."
Watson appeared emotional as she gave her winner's speech and told the BBC after the ceremony, "It was such a disturbing place to go. In my speech I was very overwhelmed I forgot to thank Janet Leach, she gave very generously to us.
"The public perception of the West case is a tabloid-driven view and then I read the script and it was a very intelligent piece full of integrity. It's a deep abyss right in the middle of our society."
Appropriate Adult enjoyed a triple win at the London ceremony - Monica Dolan won Best Supporting Actress for her portrayal of Rosemary West, Fred West's wife. Sherlock's Andrew Scott fought off competition from his co-star Martin Freeman to win Best Supporting Actor.
Beloved Australian entertainer Rolf Harris was awarded a BAFTA Fellowship in honour of his lengthy career, and as he was applauded he declared, "Thank you so much, that's very moving", before adding, "How nice to be presented with this... I can't begin to tell you just how humbled I am by being here in this distinguished company, so many previous recipients of this BAFTA Fellowship."
Other winners included Shane Meadows' This Is England 88, which took the Best Mini-Series prize, Doctor Who writer Stephen Moffat, who received a Special BAFTA for "outstanding creative writing contribution to television", and Absolutely Fabulous star Jennifer Saunders (Female Performance in a Comedy Programme).
The ceremony also featured a memorial segment, remembering the stars lost in the past 12 months, including Davy Jones, actresses Anna Massey, Googie Withers and Betty Driver, presenters Jimmy Savile and Bob Holness, actors Peter Falk, George Baker and Colin Tarrant, and comedian Frank Carson.
Presenters at the ceremony included West, actresses Helen McCrory, Melissa George and Emilia Fox, and actors Benedict Cumberbatch, Matt Smith, Sam Claflin and Timothy Spall.