petrol bomb 
noun British
A crude bomb consisting of a bottle containing petrol and an improvised cloth wick that is ignited just before the bottle is thrown at the target.The youth, who cannot be named for legal reasons, claimed he was not the person caught a dozen times on police videos throwing missiles and a petrol bomb....
- A quick-acting police officer managed to put out a fire after a petrol bomb was thrown through a shop window.
- A few minutes later police were alerted to an incident at nearby Quickthorn Place in which a petrol bomb was thrown at a house but failed to ignite.