Marvin Humes, Aston Merrygold, Oritse Williams and Jonathan ‘JB’ Gill were performing in Birmingham at a Christmas lights switch-on when fans surged forward.
The metal barriers collapsed as the 20,000 fans saw the boys take to the stage.
Four people needed hospital treatment and 60 others were hurt.
‘We are very sorry for the people who were injured,’ says Marvin.
‘After we opened the show the police took the decision to cancel the gig for public safety. The safety of our fans is so important to us.
‘It was meant to be a great event with some other amazing acts on the bill and we’re just gutted that everyone’s day was spoilt.’
The event was stopped immediately and there is an ongoing investigation into what actually happened.
Alexandra Burke and the Sugababes were also due to perform.
‘It was awful, I felt really frightened,’ Alexandra wrote on Twitter. ‘Please be safe guys. So gutted. All this ain’t worth getting hurt!’