Arsonists came within minutes of causing an explosion in a busy residential area.

They created a time-bomb by wrapping a gas cylinder in rags, placing it in a caravan and setting fire to the foam furnishings.

Smoke was spotted coming from the caravan on land in Gordon Road, Portslade, by staff at the nearby Tesco store in Station Road just after 7pm.

Firefighters risked their lives to douse the flames before the cylinder exploded and then spent a further 15 minutes cooling it down.

Sub officer Stuart Black said: "It could have exploded and taken out half of the houses nearby. It could also have killed two of my officers who were inside the caravan when they discovered the cylinder.

"It is bad enough vandalising and torching a vehicle but to set a bomb off inside was crazy.

"There were houses only 40ft from the caravan.

"Luckily staff at Tesco spotted it so early and called us in. Another five minutes and it would have exploded and somebody would have been hurt without a doubt."

Mr Black said the arsonists had taken the cylinder from its position outside the caravan and placed it inside and wrapped it in curtains.