The blaze at Haven Village, in London Road, was reported to the fire service shortly before 2pm on Tuesday (July 19) – approaching the hottest part of the hottest day on record.
This morning, a spokesman for the service said: “The fire at Charlston Terrace has left the building structurally unsafe so we will be unable to carry out a detailed fire investigation.
“However, information from the crews who attended initially has led us to conclude that this fire was started initially by some kind of discarded smoking materials outside the building. In the hot dry conditions, this has ignited quickly and spread to a gas source, allowing fire into the building.”
Demolition work is thought now to be under way.
A spokesman for Boston Borough Council said its Housing Team is providing advice and assistance to anyone who is now homeless.
Christian Allen, assistant director of Regulatory Services at the authority, said: “I am eternally grateful that there have been no injuries or worse due to this fire and my thoughts are with the families who have lost their homes and their possessions in such horrible circumstances."
“Our thanks go to the fire service personnel and council officers who have responded to this tragedy,” she added. “My sympathies are with the families who have lost their homes in this awful blaze.”
IN PICTURES: Boston apartment block blackened by fire