Police said the firework was thrown into the shop floor area of the High Street store at about 2145 BST on Wednesday.

The firework exploded into a magazine display case, sending large pieces of plastic flying around the shop and setting some magazines alight.

The youth who threw the firework was seen to run off and police said although a member of the public gave chase, he managed to escape.

Anyone with information about the incident is asked to contact Wellingborough Police.