Twelve fire engines and around 80 firefighters tackled the blaze in Woodley Close.
Around 20 people left the building before firefighters arrived and a woman and child were treated at the scene for smoke inhalation.
The fire was producing a significant amount of smoke and people in the area were advised to keep their windows and doors closed.
Crews have brought the fire under control but will remain at the scene for some time to fully extinguish the fire and dampen down.
A 64-metre turntable ladder was deployed at the scene as a water tower to help fight the fire from above.
Drivers are asked to continue to avoid the area and to expect traffic disruption, including on London Road near the junction of Arnold Road.
The Brigade’s 999 Control Officers received around 15 calls about the fire.
Photo Credit: LFB
