Police have launched an investigation after four people suffered injuries when a firework exploded in the crowd at a popular bonfire event.

A record 20,000 people attended the Fawkes in The Walks event in King's Lynn on Friday but some revellers were left shocked after a rocket was set off into the busy crowd.

Four people suffered injuries to their hands and necks needing treatment by paramedics at the scene.

One woman with burns was taken to the Queen Elizabeth Hospital for further treatment.

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In a statement, the Borough Council of King's Lynn & West Norfolk's news and events team said: "We're aware that one firework entered the crowd last night which was not one from our Fawkes in the Walks display.

"Our doctor and paramedics attended to four people in the park."

As part of their investigation, officers are appealing to the public for anyone who may have any information.

Anybody who may be able to help should contact Norfolk Constabulary on 101 quoting crime reference 36/78256/24.