Firefighters from Havant and Emsworth were scrambled to a home in Havant Road, Emsworth, on Tuesday to reports of a blaze inside the living room of the property.
When crews arrived, at about 9.30pm, thick smoke had engulfed the living room of the house - but officers had no idea what was causing the blaze.
"It was a really bizarre one," said Havant crew manager Glenn Kavanagh. "When we arrived, the whole living room and downstairs was filled with smoke. It was difficult to see what was on fire."
Confused, they deployed their thermal imaging camera into the room to hunt down the source of the smoke.
After a few minutes of searching, officers finally uncovered a small smouldering patch of wood on an ‘antique-style’ desk.
But the team was stumped as to how the desk managed to catch fire.
"We had no idea at first how it started," said crew manager Kavanagh. "But then we found a broken lamp nearby and realised what had happened."
Crews soon managed to piece together the mystery of the fire.
"At some point the lamp had been knocked over and hit the wooden antique desk in her living room," crew manager Kavanagh said. "It broke the top part of the lamp, which heated up the desk.
"The heat had been enough to create a small burn that was smouldering and had been burning for a few hours.
"It really was a strange one. The fire was so small we could put it out with a glass of water in the end."
However, despite its small size, crew manager Kavanagh said it could still have been a potentially deadly fire, if it had been left for much longer.
"All fires are dangerous," he said. "This one filled the downstairs with smoke. So it would have been very difficulty for the lady to breath in. She was also quite a frail, elderly lady with mobility issues.
"It was still dangerous. If it had been burning left a lot longer or the lady had been asleep it would have developed a lot more."
In the end, officers removed the desk from the house to extinguish the fire. They also used a fan to clear the downstairs of smoke.
About 10 officers attended the blaze.