Wikipedia dixit :

« Punkadiddle » is thought by many to be Oldfield’s jocular take on punk music, a genre which he has stated in the past to be not at all impressed with. In fact, Virgin Records’ rampant signing and promotion of many punk bands while not promoting Oldfield’s albums is seen as one of the sources of the rift between him and the company. When the track was performed by Oldfield on tour, he and his band would all perform the song bare-chested.