YOBS targeted a vulnerable family by posting a firework through their letterbox.

The mother and her two daughters were said to be ‘frightened to death’ by the incident, which happened around 8.30pm on Tuesday night in Formby Close, Highercroft.

Fire chiefs have now given the mother, aged 40, and her two daughters aged, 16, and 12, extra protection usually reserved for victims of arson attacks.

They confirmed an 'air bomb repeater' firework had been pushed through the front door and that they’ve taken special measures to stop it happening again.

Watch Manager Steve Harrison at Blackburn Fire Station said: “The air bomb repeater firework frightened the occupants to death.

“This happened in the early evening and could have had very serious consequences as there were children at the property and it could have caused a significant injury to anyone within.”

A specialist incident intelligence officer from Lancashire fire and Rescue has now fitted preventative measures on the door to stop it from reoccuring.

A Lancashire Fire and Rescue spokesman explained the measures were only used in rare circumstances where a person had been targeted by arson or had been subjected to specific threats of arson.

He said: “In this instance, because of the time of year and the fact that the family are particularly vulnerable, the officer fitted a temporary measure for their peace of mind.

“The device is like a mesh material satchel, which screws to the back of the door and has no air inside.

“Anything such as a firework which is put through is extinguished.

“We will re-visit the family after Bonfire night, speak to them and possibly remove it if they feel happy.

“This is only done in very rare circumstances, but is an option available to us.”

A neighbour who helped calm the ‘panicked’ family said: “I went to help afterwards and the children were very upset and frightened. Their cats were under the bed, shivering.

“We think it is a group of kids from the area. The family occasionally get picked on.

“It’s a stupid thing to do, but they shouldn’t be sold the fireworks in the first place.

"Who is giving them to children?”