Now that Band Aid's "Do They Know It's Christmas?" has become the biggest record ever in England with more than 2 1/2 million sold, the man who put the superstar cooperative together to raise funds for the Ethiopian famine appeal is trying to maximize the income. Bob Geldof, lead singer of the Boomtown Rats and the star of the movie "Pink Floyd -- The Wall," is working getting the United States and Britain to surrender sales tax revenue so that more money can go to feed the starving.

This came about after Geldof watched a BBC news special on the famine in Ethiopia on Dec. 1.

"You see a child dying on your television screen and you think, I can't accept that, so you do what you're capable of doing," Geldof says. "I had an opportunity to do something besides just put my hand in my pocket, which a lot of people did. But that seemed inadequate to me: no matter how much you gave, it wasn't enough. The only way I could commit myself is by doing what I do, which is write songs and sing them. I just took it in stages -- the idea, the song, getting the people, then the studio, getting the record out fast, then unashamedly plugging it."

Geldof did more than just get the people; he collected 37 friends and acquaintances, who also happened to be some of England's biggest pop and rock stars, including Sting of the Police, Phil Collins, Paul Young, all the members of Duran Duran, Spandau Ballet, Bananarama and the Rats, and some members of U2, Wham, Style Council, Ultravox, Status Quo and Culture Club. James Taylor and Robert (Kool) Bell were the only Americans involved in the one-time project. They recorded the song (written by Geldof and Midge Ure of Ultravox) in Trevor Horn's obviously crowded studio in one day; the single sold more than a million copies in its first four days of release.

Geldof says he and the others involved in the project had learned a number of lessons from controversial rock concerts in behalf of Bangladesh and Kampuchea. "The organization has to be incredible," he says. "You can't leave it in other people's hands. You have to make sure all the legalities are worked out before you do anything. If you get an idea, move with speed. Only speak to people who can make decisions. Keep track of where the money's going. See that nobody gets paid, that everything is done for free and make sure you're not dealing with a totally corrupt government."

The Band Aid project has been helped by donations of advertising space in many magazines and papers (England's Daily Mail gave it the front page) and by retailers waiving profits. There's even an instant video, shot during the recording session, with introductions provided by David Bowie and Mick Jagger. In America, more than a million copies of "Do They Know It's Christmas?" were shipped to retail outlets last week. In Europe, Japan and Australia, comparable numbers were shipped. All of which is pleasing Geldof, who admits that the song's chart position is far less important than its sales. "I'm going to be asking Americans to suspend taste, choice and judgment to keep someone alive this Christmas," he says.

"But it's a complete irrelevance," he adds. "The point is a monstrosity of this kind is above politics, it isn't something to be argued over or thought about or rationalized . . . It doesn't matter who gives what aid or who is to blame. The point is 28 million people in the Horn of Africa may die within 12 months: that is the point. The issue is to save them."

Geldof is trying to insure that "not one penny will be paid in administrative costs." In January he will travel to Ethiopia, though he had not originally planned to do so: "I was ashamed of the flesh on my bones, and what they don't need is whitey parading with hands behind his back taking another meal with a troop of cameras.

"But I didn't anticipate the scale of the record being so big. Right now, a lot of money is going to be put in that trust fund and it's up to us to make sure we understand totally the problems involved and figure out the most effective way of getting that money into the country."