Bush, 56, is in London till October 1 for her first live shows in over 35 years entitled, 'Before the Dawn', reported Contactmusic.
At 9pm an announcement was made over to the restless crowd, letting them know the show now had a new start time of 9.05pm and new finish time of 12 to 12.10pm.
The audience was then told that refunds were available for those unable to stay for the whole performance, however in order to claim their money back they would need to leave the venue by 9.45pm.
"Katebush delayed till 9, won't finish till 12.15 but only people who leave before 9.45 get refunds. So we'll see half the show but no refund," one tweeted.
While another said, "EventimApollo KateBushMusic I'm so so disappointed. I have waited so long and now I'm going to miss most of it so I can bloody get home."
When Bush eventually made it on stage, she told the audience "Thank you so much for being so patient. It was entirely beyond our control, but we hope that you enjoy the show.