SHOCKED residents have revealed their terror after a huge fire broke out at a Southampton city centre building.

Police sealed off the scene near the A33 Kingsway with officers warning onlookers not to breach the cordon because “boulders of hot ash” were flying from the burning building.

People living nearby were evacuated as clouds of smoke started filling flats and had to be found emergency accommodation.

At the height of the blaze flames erupted from the top of the building and a thick plume of black smoke started drifting across the city.

One student said he saw the fire as he left nearby City College.

He added: “It looks as if the flames started at the top of the building. I stopped to watch and saw a huge lump of black ash fly out and go though a window.”

Another witness added: “We saw smoke and then flames but the fire crews were already here. It seemed like they had it under control very quickly.”

Hampshire Fire and Rescue Service (HFRS) said ten appliances were sent to the blaze.

The service originally said the fire broke out in a derelict building but later described it as a timber-framed building which was under construction.

The fire later spread to the roof of next-door flats.

Two of the appliances sent to the incident were from St Mary’s fire station only a few streets away.

Crews were joined by colleagues from seven other stations – Hightown, Redbridge, Eastleigh, Hamble, Romsey, Fareham and Bishop’s Waltham.

Equipment used to fight the fire included two aerial platforms, which enabled firefighters to tackle the flames from above. Nine jets, two hosereels and a fan spray were also deployed.

People who took to social media as the drama unfolded said the blaze was visible from various locations including Southampton Airport and the Itchen Bridge.

One person posted: “They shut the road off but we had burning black lumps of something falling nearby.

“I have not heard of any injuries but it did look nasty.”

South Central Ambulance Service personnel were placed on standby because of the scale of the incident and the number of firefighters involved.

A spokesman said an ambulance, a rapid-response vehicle and the Hazardous Area Response Team were sent to the scene, but he added that no casualties were reported.

HFRS received what it described as a “high number” of 999 calls about the fire, which engulfed the entire building.

Last night an HFRS spokesman said an inquiry into the cause of the blaze would begin as soon as it was safe for investigators to examine the remains of the building.

Residents of the St Mary’s Street area living close to the scene of the fire were told to leave their homes, and a reception centre was set up at nearby City College.

Around 30 people of all ages were gathered there yesterday evening.

St Mary’s Street resident Andrea Vrankova, 44, who lived next door to the building which caught fire, told the Echo: “I had to leave the house. I could feel the heat. I took my passport and ran away.

“The fire was getting bigger and bigger by the time I got out.”

Sisters Magdalena and Julia Szymczak, who lived opposite the scene of the fire, watched the flames take hold and went to warn neighbours.

Magdalena said: “It started and spread in a few seconds. Something landed on my building.

“Our landlord evacuated us.”

Another resident of St Mary’s Street, who did not want to be name, said: “I was in my flat and I saw the smoke. I grabbed some clothes and ran. I was shocked and scared. I didn’t think about anything, I just grabbed my things.”

Balbinder Singh, who owns H&R Computers in St Mary’s Street, said: “I heard some noise and locked the shop and ran outside. I could feel the heat.

“I am praying my shop is okay.”

Barber Aram Abbas, 18, from Sholing, who works in the area, said he was frightened that the fire would spread to his shop.

“I thought it would burn all the way through the block,” he said.