Naughty Adele at BRIT Awards Show

ADELE won Best Album at the U.K.'s BRIT Awards last night . . . then FLIPPED THE BIRD during her acceptance speech.

She was angry because the host cut her off.  Apparently, her speech was running long . . . and he had to introduce the band BLUR, who was performing to close out the show.

(Photo Credit: PA Photos/Landov)

Afterwards, Adele apologized, and said the middle finger was for the show's producers.  She said, "I was cut off during my speech but I wanted to thank the British public for all their support."

"I was held up with my voice and troubles but the album kept walking without me.  I flipped the bird for the suits at the BRITS who cut me off.  Sorry if I offended anyone but it was for them, not for the fans."

The host was also sorry it went down like that.  He said, "I don't understand quite why I was made to [cut her short] . . . she's the biggest star in the world.  I don't understand what happened but I'm upset about it."

"Blur played for 11 minutes, and she didn't get [the] chance to say thank you once." 

(Technically, she said "Thank You" four times, but they were just general "Thank Yous" to the crowd . . . not to anyone in particular.)