A song on Paul McCartney's next album slams critics of his wife, Heather Mills.

Since marrying Paul in 2002, Heather has been the subject of claims that she is a gold-digger, and many critics have accused her of enjoying the media spotlight too much.

However, the new song hits back at the media with lyrics including, "Said she was a gold digger/ Said I was a fool/ Said I was rich, crazy, lonely/ She was beautiful but crude."

A source close to the star told the Herald Sun, "Paul is so angry about what people have been saying about Heather. Writing is his way of expressing himself so it is no surprise that he has composed this song.

"Heather has been upset by a lot of the criticism about their relationship. It has really dragged her down, and he can't stand to see her so low. Paul has written the song for his new album. He is presently deciding whether to put it on as he knows this will stoke up even more problems."