This free concert was a tribute to Brian Jones who was found dead in his swimming pool on 2 July, 1969. There was speculation as to whether the event should go ahead but Mick Jagger quashed rumours by saying that it would be what Brian would have wanted and that ...it's because of our love for him that we are still doing it.
The accompanying letter states that the original owner of this pass kept boxes of butterflies in his fridge the night before, which were later released in a flurry during the concert.