Amy Winehouse's father Mitch is convinced that one of the singer's friends spiked her drink with ecstasy.

The 54-year-old, who found his daughter in convulsions on Monday night and rushed her to hospital, is adamant that someone put the drug in his daughter's drink, which caused her to fall ill.

The incident, which resulted in the 24-year-old star being given oxygen and spending the night under observation, was initially thought to have been caused by the medication Amy is on to help her kick her crack cocaine addiction.

However, Mitch insists that this is not the case.

An insider said in The Sun: "Mitch is furious. He's certain someone put E in Amy's drink — and he’s determined to get to the bottom of it.

"He is convinced that one of her hangers-on was responsible and he’s waiting for a toxicology report to show what caused her fit.

"If his suspicions are proved right, he wants someone to be punished. He is seriously unhappy about Amy’s flat being a stop-over for randoms and wants an end to it."

Winehouse was discharged from the University College Hospital yesterday.