Justin Bieber went on stage late Monday night at London's O2 Arena, leaving many of his young fans angry or asleep.

Stories differ as to whether Bieber was two hours or 40 minutes late. Either way, fans and their parents weren't pleased. Britain's Daily Mail reported "hundreds" of fans left before Bieber hit the stage at 10:23 p.m., as parents were supposedly led to believe the entire show would be over by 10:30 p.m. Bieber ended up cutting his show by 30 minutes, due to curfew restrictions.

A source told MailOnline that crowds booed Bieber when he took the stage, after sitting through warm-up acts Cody Simpson, Jaden Smith and Carly Rae Jepsen. There were reports of kids falling asleep before Bieber went on. Estimates differ as to whether fans waited 45 minutes or 90 minutes for Bieber to hit the stage, after Carly Rae Jepsen's set.

An audience member told MailOnline: 'It's disgraceful, so many children were distressed and left heartbroken... . Many had been looking forward to seeing Justin for weeks.'

Great. Thanks, Justin Bieber, for making North America look bad.

The 19-year-old Bieber -- who, if I can point out, is CANADIAN -- took to Twitter on Tuesday and blamed his tardiness on "technical issues" and said he wasn't two hours late.

"Last night I was scheduled after 3 opening acts to go on stage at 935 not 830 but because of some technical issues I got on at 10:10..so... I was 40 min late to stage. there is no excuse for that and I apologize for anyone we upset. However it was great show and Im proud of that..."

Really? You ticked off the entire British Empire, and you're proud of that?

He further tweeted '...and tonight we will run on time and look forward to putting on an amazing show for everyone in attendance. 'My relationship with the media is not always easy but im trying. Im all about the music and the performance and I respect my fans."

Blame the media all you want, but at least we try using correct punctuation. Most of the time.

The O2 eventually apologized for the lateness of the show, but didn't offer any explanation as to why Bieber was late. The venue supposedly contacted ferry and train services, alerting them that fans needed transport later than was originally planned.

Contact Tony Hicks on Facebook at www.facebook.com/BayAreaNewsGroup.TonyHicks, or on Twitter at twitter.com/insertfoot.