Three people were taken to hospital following a blaze on the edge of Hampstead Heath.
Four fire engines and around 25 firefighters were called to tackle a house fire in South End Road just after 3.05am on Friday (October 13).
Half of the ground floor and part of the first floor of a mid-terraced house under renovation were damaged by flames, London Fire Brigade said.
Two adults and a teenager left a neighbouring property and were taken to hospital after suffering from smoke inhalation.
The fire, under control by 4.30am, is believed to have been accidental and caused by "hot works carried out at the property", an LFB spokesperson said.
Hot work includes any operation that uses open flames or the local application of heat and friction such as weldering or soldering.
According to Zurich insurance company hot work "is frequently used during construction, renovation and maintenance, including planned and emergency repair works".
Fire crews from West Hampstead, Kentish Town and North Kensington fire stations attended the scene.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here