What is ‘shatter’ cannabis, the drug blowing up houses?

A drug dealer was jailed for 14 years after his cannabis lab blew up, killing his 7-year-old neighbour. He was using butane gas to produce ‘shatter’. So what is this super-strong cannabis, why is it so popular and what makes it so explosive? In this 18:58-minute video, ITV Tyne Tees shares what you need to know.