Devon and Cornwall Fire say a fire at a Homebase store is likely to cause major traffic disruption today as it is so close to the A38.
80 firefighters have been tackling the blaze which now seems to be under control.
Investigators will begin trying to determine the cause of the fire later today.
80 firefighters have been tackling a blaze at a Homebase in Liskeard.
Crews were called to the store shortly before 2am this morning and the fire took several hours to bring under control.
The roller shutter doors of the building were ripped open using disc cutters so firefighters could get better access.
Cornwall Fire and Rescue Service have said a fire started at Great Trethew Manor Hotel at Horningtops near Liskeard on Wednesday was accidental.
Fire Investigators have concluded their examination of the scene.
An investigation began today after fire swept through a hotel in Cornwall. At its height, the flames were so fierce that the crews had to withdraw for their own safety. Around 20 firefighters stayed there throughout the night.
More than 20 firefighters remained at the scene of a major fire near Liskeard overnight. The Great Trethew Manor Hotel was gutted in Tuesday's blaze and crews used hose reels to damp down the building.
The hotel is continuing to smoulder but Cornwall Fire & Rescue Service says it plans to begin the investigation into how it started later this morning (Wednesday).
This video was filmed by firefighters at the scene.
A country hotel in Cornwall has been completely gutted in a serious fire this afternoon. There are no reports of any injuries at Great Trethew Manor Hotel near Liskeard. There are however reports the fire was so fierce at one point, firefighters had to be withdrawn for their own safety.