Four people have been taken to hospital and scores more injured at a Christmas lights switch-on featuring X Factor runners-up JLS.

The incident occurred after the band took to the stage at the event in Birmingham City Centre on Saturday, when a metal crash barrier penning the crowd in collapsed.

According to the local ambulance service around 60 people needed treatment. The planned concerts and lights switch-on were subsequently cancelled.

One woman in her thirties suffered serious crush injuries to her pelvis, shoulder and limbs while a teenage girl sustained crush injuries to her back and legs. Another two people received hospital treatment for broken bones.

Alexandra Burke, who was also at the event, was reportedly rescued from the crush by her manager.

Reports say that thousands more fans than anticipated showed up to the switch-on ceremony, which was also due to feature a performance from Sugababes.

A spokesman for West Midlands Ambulance Service told the BBC News website: “There was a very large crowd, believed to be 21,000 people, in attendance and there had been a crush outside the event trying to get in as JLS started playing.

“A metal fence collapsed trapping a couple of people underneath. As the barrier collapsed it’s believed people were trapped and trampled underneath it.”

JLS said in a statement that they were “so so sad” about what had happened.

It was meant to be a great event,” said member Marvin Humes. “We’re just gutted that everyone’s day was spoilt.”

“It should have been a great gig with other artists like Alexandra Burke and Calvin Harris.

“We just hope that everyone who was injured has a speedy recovery.”