Passers-by were left stunned after a fire engulfed an industrial depot opposite St Mary’s Stadium this afternoon.

Smoke could be seen emanating from Polystar Plastic’s warehouse on Melbourne Street shortly after 1pm, with the fumes being seen from as far away as the Isle of Wight.

One hundred firefighters and 18 fire engines with assistance from police and paramedics combatted the fire, with the unit being cordoned off.

Marine Parade and Britannia Road were closed as a result.

Stunned workers, shoppers, and passers-by gathered behind the police cordon ‘in shock’ at what was unfolding.

Harry McBain, a 19-year-old student from Solent University, told the Echo: “It was a shock, I saw the huge clouds of smoke from university.

“I saw that everyone was posting about it on social media, so I thought I had to go and check it out. It was unreal.”

READ MORE: Fire breaks out near St Mary's Stadium

Delivery driver Sebastian Rusu, 29, had been shopping in the city centre when he first saw the smoke.

Daily Echo:

Speaking to the Echo earlier this afternoon, he said: “I was in the city centre and saw the smoke and thought it was coming from the football stadium.

“I followed the smoke and arrived here.

“I’ve been here for around 30 minutes, and everything has been moving really quickly.

“The police have moved us back and we’re just waiting to see what happens now.”

Nikki Delaney was in the area when the factory went up in flames.

She said: "The flames are high and it's getting worse.

"The heat from the flames is a lot and I'm not even close."

Throughout the afternoon, firefighters battled with the flames, which destroyed most of the building.

Piles of rubble were all that remained of large chunks as of late afternoon.

Speaking to the Echo at around 5.30pm, Malachi Crawfield-Blackthorn said: "Me and my brother we were in IKEA around 1pm when we saw the smoke and we knew he had to get here.

“Initially we thought it was nearer the city centre and when we got here I initially thought ‘it it gonna take out the stadium?’ but fortunately it seems like it’s under control now.

“It was a torrent of black smoke when we got here, it was wider as well.

“I was just hoping no one gets injured and the fact there were no casualties is a massive blessing."

Southampton FC were due to be playing a Championship fixture against Preston North End that same evening but were forced to postpone the match after ‘consulting with the local authorities.’

He added: “I’m sure some people were annoyed that the match was cancelled but the good news is that no one was injured.”

Following the blaze, in a statement a spokesperson for Hampshire and Isle of Wight Fire and Rescue commented: "Crews are currently attending a fire in Marine Parade Southampton. The initial call came in at 1.05pm.

"The fire is affecting four industrial units near St Mary’s football stadium.

"There are currently eighteen fire engines, two aerial ladder platforms and other specialist vehicles in attendance.”

They went on to say: “People in the area are advised to keep windows and doors closed due to the amount of smoke.

"Some roads local to the incident are closed and people are advised to avoid the area to allow movements of emergency vehicles."