Did Lionel Bart Write "Oliver"?

A rather surprising item in the London Independent is claiming that Lionel Bart didn't write all of the hit musical Oliver! According to the article, his former collaborator Joan Maitland wrote the book and accepted a 1% sum of royalties in exchange for her silence. There apparently have been other claims that his work was not his own. He got his start as the lyricist of Lock Up Your Daughters and composed his first score Fings Ain't Wot They Used to Be. However, Bart only had one major success with Oliver! He would follow with minor successes in the UK with the WWII era musical Blitz!, a major spectacle that even included a recreation of a London bombing and Maggie May. Afterward, his shows were major failures, including the London flop Twang! and the one performance bomb La Strada in NY. He never wrote another new musical again.