The Unthanks have won album of the year at the BBC Radio 2 Folk Awards for the ambitious, melancholy Mount The Air.
The record, which received a host of five star reviews, is notable for its 10-minute title track, which marries a traditional Dorset folk song with Miles Davis-inspired trumpet figures.
The band closed the ceremony, at London's Royal Albert Hall, by playing the song, complete with clog dancing.
Joan Armatrading also played and took home a lifetime achievement award.
Presenting the award, Radio 2's Sara Cox called Armatrading an "understated trailblazer".
Armatrading said she was "surprised and delighted" to be recognised for her contribution to British music, including songs such as Weakness In Me, Love and Affection, Willow and Down To Zero, which she played on stage.
"I have heard people say that awards don't mean much to them but for me, being given an award means that I am being told that my music is being appreciated.
"As a singer-songwriter that's one of the main things I'm asking for."
Norma Waterson, the "grande dame" of British folk, also won a lifetime achievement prize, presented by Richard Hawley, who remembered quizzing her about the folk scene of the 1960s.
"Did you lot do loads of drugs," he asked. "No," she replied, "but we ate a lot of pickled onions."
Accepting her award, Waterson paid tribute to her late brother, Mike, and sister, Lal, with whom she sang at the start of her career.
"It shouldn't just be me here," she said. "Singing with them was like being in heaven."
The Unthanks were presented with the best album prize by Sherlock star Martin Freeman, a "big fan" who praised their "blatant disregard for genre or rules".
"Their original material is already very close to being classic," he observed.
Several winners and presenters also noted the recent surge in interest around folk music.
Receiving the Good Tradition Award, for his contribution to the preservation of folk music, John McCusker marvelled at the "explosion of young people, who are not only playing with technical brilliance, but with such passion and enthusiasm".
Elsewhere at the ceremony, singer-songwriter Sandy Denny was admitted to the hall of fame.
Denny, who died of a brain haemorrhage in 1978 at the age of 31, is considered one of the most influential vocalists in the history of British folk, both as a solo artist and through her work with The Strawbs, Fairport Convention, and Fotheringay.
"The recordings she left behind have captivated, moved and inspired the next generation," said presenter Julie Fowlis.
Among her acolytes was Rufus Wainwright, who paid tribute by performing the classic Who Knows Where The Time Goes?, a song which was once voted the favourite folk track of all time by listeners of BBC Radio 2.
US artist Rihannon Giddens won folk singer of the year, following the success of her debut solo album, Tomorrow Is My Turn.
The Grammy-nominated record was produced by T Bone Burnett, who approached the singer during rehearsals for a concert based on the soundtrack of the Coen Brothers' film Inside Llewyn Davis and insisted they record an album together.
Teesside trio The Young'uns, who specialise in a capella performances, won best group for the second year in a row; while best duo went to husband and wife Kathryn Roberts and Sean Lakeman.
The full list of awards was as follows:
- Folk singer of the year - Rhiannon Giddens
- Best duo - Kathryn Roberts & Sean Lakeman
- Best group - The Young'uns
- Best album - Mount The Air, The Unthanks
- Horizon award - Sam Kelly
- Musician of the year - Andy Cutting
- Best original track - Mackerel, The Rheingans Sisters
- Best traditional track - Lovely Molly, Sam Lee
- Young folk award - Brighde Chaimbeul
- Lifetime achievement awards - Joan Armatrading and Norma Waterson
- Good tradition award - John McCusker
- Hall of Fame inductee - Sandy Denny
Hosted by Mark Radcliffe and Julie Fowlis, the ceremony was broadcast live on BBC Radio 2 and can be heard again on the BBC iPlayer.
It will also be televised on the BBC Red Button from Saturday 30 April until Thursday 5 May.