Teen pop sensation Justin Bieber has made a grovelling apology after turning up late for his sold-out concert at London's O2.

The 19-year-old singer faced a backlash from dedicated fans and furious parents for his behaviour, which forced hundreds to leave early in order to catch the last train home.

Reports had suggested that the star only graced the stage at 10.35pm - two hours after the scheduled time and 25 minutes before he was due to finish.

The Baby hitmaker blamed the delay on technical issues and insisted that he had only been 40 minutes late for his set. He was adamant that his start time was 9.30 and that he had got on stage at 10.10.

"There is no excuse and I apologise for anyone we upset," he said on Twitter. "However, it was great show and I'm proud of that."

He added: "I never have any intention to upset or let anyone down. And I'm not okay with things being exaggerated. Once again sorry for anyone upset."

Fuming parents who shelled out between £57 and £68 for tickets vented their anger online.

Lloyd Becker said that his little girl was devastated by Bieber's behaviour.

He told MailOnline: "I called the O2 to find out what time the show was ending. They told me that Bieber was on at 8.30, finishing at 10.15. But he didn't even come on until 10.35.

"My brother was also there with my nephew but by the time Bieber came on, the kids were fed up and half asleep. They stayed for half an hour and then left, so they missed all the best songs.

"Keeping the fans waiting for two hours is an absolute disgrace. Isabella got to bed after one in the morning and then had to get up for school. And I know that at least two or three children have missed school because they couldn't cope with the late night."

A spokesman said the O2 has asked promoters to explain why the star was late.