Barry, 27, told the News of the World: "My mind's made up, I want to join Liverpool. There's no going back, it's time for me to move on. I'm desperate to play Champions League football and that's why I have to leave Villa.
"I hope the Villa fans understand. I have given my all for the club for 10 years and I'm only leaving because now I need to test myself at the very highest level.
"And I can honestly say if Villa were in the Champions League I wouldn't even consider leaving this great club."
Barry added: "I am obviously flattered that someone as successful as Rafa Benitez thinks so highly of me.
"And that he's not been afraid to put his valuation of me in black and white for Villa and all the world to see.
"But have Villa offered me anything to try to persuade me my future is at Villa Park not Anfield? Not a thing."