Pictures from the night show plumes of black smoke rising over St Peter Port with one image which was shared extensively on social media capturing the flames coming out of the upstairs windows.
Guernsey Fire & Rescue Service Duty Officer Tim Falla said 16 firefighters, two water tenders and the turntable ladder were used to tackle the blaze.
“The turntable ladder was here for two reasons, a Plan B, incase we were losing it, and guidance to see which way the fire was going. We have a pre-plan for these fires, the idea is the BA [breathing apparatus] crew takes a lead, their brief is search and rescue and to make sure no one is in the building, then if they come across the fire, to tackle it. The second team then goes in.”
The flat above and below the one ablaze had also been damaged, he added. Insurers, possibly including a forensic fire investigation team from the UK, were due on site, Mr Falla added.
Initial calls to the Joint Emergency Services Control Centre were received at 09:22, with the fire being extinguished about two hours later.
St John Ambulance Service initially sent an Incident Officer and double crewed ambulance to the scene. Once it was established everyone had been evacuated the ambulance was stood down, but the incident officer remained on scene to provide bottle water to the firefighters to reduce the risk of dehydration.
Smashed windows and extensive fire damage were clearly visible after the fire had been extinguished, with broken glass littering the street outside.