Teen pop idol Justin Bieber has angered parents by emerging onstage for a concert at London's O2 Arena almost two hours late.
While the 19-year-old singer's young fans were kept waiting, frantic parents converged on the venue expecting to pick up their children.
It follows reports Bieber's gig in Nottingham on Saturday also began late.
Fans tweeting from inside the O2 said there were boos from some in the crowd almost an hour before he emerged.
Speaking outside, one fan said: "They were playing Michael Jackson song, after song, after song - it was so annoying.
"Everyone was on edge and as more time passed, everyone was getting more worried and booing."
Tracey Wilson, from Hoddesdon in Hertfordshire, was at the concert with her daughter.
'Just a shambles'
She told Tony Livesey on BBC Radio 5Live that Bieber had been due to start at 20:30 GMT.
She said: "The support acts came on but they ran over until about 8.50pm, and then we sat there until 10.20pm for Justin to come on.
"A few of the parents went up to the information desk to complain and they were saying there's nothing they could do and that 'It's just Justin Bieber's production team'.
"We said that was all well and good, but most of us have to get trains... it was just a shambles. I said we've really got to leave at 10.50pm to get the last train."
She added that people in the crowd began booing at about 21:30, almost an hour before Bieber's act eventually started.
Another parent Wayne Parsonage, who said he paid £400 for three tickets, tweeted that he ended up missing the performance so he could make the last train home, and later added: "Disgusting!! Waste of my time and money...never again."
Richard Hayward, from Folkestone, Kent, said he had to deal with an "inconsolable" daughter who was in floods of tears as she was only able to see 15 minutes of the concert before they had to get the last train home.
"She had set a countdown to the concert on her phone, and her bedroom wall is covered in Justin Bieber posters," he added.
'Counting his millions'
Andy Ward, from Berkshire, waited for his daughter outside the arena until after midnight.
"Kids were crying because some of them did not have the opportunity to see Justin Bieber," he said.
"I feel frustration. It is outrageous that there was no communication from the organisers. It makes you very angry that he can get away with it."
He said his daughter sent him a text message at 22:20 saying: "he hasn't even come on dad this is a joke".
Mr Ward said he finally got home at 02:30 and that he had to be up two hours' later for work.
"Needless to say I am sure that Justin Bieber is resting, sleeping and counting his millions with not even a care in the world for the inconvenience caused; the tears of the girls who had to leave even before he came on due to having to get the last trains home; the additional expense of car parking, taxis and the knock-on effect today."
No-one connected to the show has commented, but the venue apologised for the late start via its Twitter feed saying: "Justin Bieber is now on stage and apologises for the lateness of his show".
On Tuesday morning it tweeted that it will be "exploring all available options to ensure this doesn't happen again".