After the devastating fire at new build block of flats in West Hampstead yesterday saw families evacuated and five balconies destroyed, London Fire Brigade revealed they believe a discarded cigarette butt caused the blaze.

The brigade’s investigators said the fire was thought to have been started by a cigarette left in a plant pot on the balcony of the third floor of the Orwell building on Heritage Lane.

Firefighters have also issued a smoking safety warning after the inferno which left residents terrified.

The brigade said: “We would rather people didn’t smoke at all but if they do, vaping is a safer option.

“If you do choose to smoke cigarettes, it is absolutely vital you ensure your cigarette is completely out when you’ve finished smoking it.

“If you don’t, you risk causing a fire which could not only destroy your home, but also cost you your life.”