The Les Misérables star had been due to present the award for 'Original Screenplay' alongside Sally Field, but was unable to appear on stage because of his sudden illness.
Field, who appeared alone to present the award to Quentin Tarantino, stated that Redmayne was "puking his guts out" backstage.
Redmayne's co-star Anne Hathaway confirmed his illness when she picked up her award for 'Best Supporting Actress', saying: "Eddie, feel better. I would be holding your hair back, but... food poisoning is just the worst."
Les Misérables won the most awards of any film at the BAFTAs, taking home four awards in largely technical categories.
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Watch Digital Spy chat to the stars at the BAFTAs below:
Photo gallery - BAFTA Awards red carpet arrivals