A fire that saw the rescue of a mother and her two young children was likely caused by a faulty e-scooter battery or charging unit, an investigation has found.
Firefighters were called to the home in Reeves Road, Normanton, Derby, at about 03:30 GMT on Sunday.
Crews were able to break through the front door of the property and found the mother and her children - one aged three and one believed to be two months old - in a first-floor bedroom.
Derbyshire Fire and Rescue Service group manager Rob Leverton said: "This was a significant fire that caused extensive damage to the property."
The fire service confirmed the family was protected from the fire and heat as the bedroom door was closed.
They were treated with oxygen after being rescued and taken to hospital. It is understood they have now been discharged.
'Growing fire risk'
Mr Leverton added: "This was a significant fire that caused extensive damage to the property, but thankfully firefighters were able to act swiftly and save the lives of the young family who were trapped upstairs."
An investigation has now concluded the fire was started accidentally, and it is believed either a faulty e-scooter battery or charging unit caused the blaze.
Mr Leverton said: "Fires involving lithium batteries were identified as the fastest-growing fire risk in the capital, with London Fire Brigade being called to an e-scooter or e-bike fire once every two days on average last year.
"If lithium-ion batteries, like those in e-bikes and e-scooters, are not handled and cared for correctly, then the consequences can be devastating.
"I would therefore urge everyone who has one of these modes of transport to follow our safety advice - do not charge your battery overnight, always use the manufacturer approved battery and charger, and do not tamper or modify your battery."