VIDEO: Whitney Houston Bombs In London

Whitney Houston's first concert in London in more than a decade left concertgoers upset, RadarOnline.com has learned, as the 46-year-old diva came out Sunday looking bloated and disheveled, struggling to hit high notes and delivering a performance some fans felt was so awful, they left asking for refunds.

"I remember her 20 years ago," concertgoer Dave Law said of Houston. "She's not a patch on what she was."

Houston's singing ability was so impaired by what she said was a respiratory infection, that she struggled through her song I Will Always Love You. At one point, while trying to perform her other hit ballad The Greatest Love Of All, she quit after getting out only a couple of lines.

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“She don't want to come, my Soprano friend. Sometimes the old girl sings, but not tonight," Houston told the crowd of 20,000 -- some of whom who paid as much as $150 for tickets -- of her vocal woes. "I want to do it, but she doesn't want to ... she's getting a little ... temperamental, even."

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Houston returns to the O2 for a performance Monday night.

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