AN eyewitness has told how she saw a red and grey device in the Manchester Arena foyer a split second before the venue was rocked by an explosion.

Emma Johnson told BBC Radio 5 Live that she was 15 feet away from the blast, which killed 22 and injured 59.

The mother was waiting for her son and daughter, aged 15 and 17, when Ariana Grande fans wearing black, white and pink merchandise began leaving and something caught her eye.

She said: “For one split second I turned and saw what I can only describe as a bright red. It was bright red with a grey panel down the front with risen bits all over it.

“It was so intense, the colour, in this crowd of people. As quick as I saw it, the explosion happened.

“There were dead bodies everywhere, and then I saw the torso, the remains of a body, left as well. It was horrendous.”

Speaking to presenter Nicky Campbell, she went on: “It was just so loud and then you just saw this flash of light and then there was just smoke and there was shrapnel everywhere, everywhere. The glass exploded, it was people screaming. Your instinct is ‘my children, my children, I’ve got to get to my children’.”

Talking about the perpetrator, she said: “They knew that they couldn’t get into the arena because obviously there are security guards on every single door but there’s no security guards stopping people coming into the foyer so anybody can walk in at the end of the night.

“It just happened so quickly. I just can’t comprehend it.

“My heart goes out to all those that have lost loved ones.

“You sit at home and you watch these things on TV and you think how awful, how terrifying. It is the worst feeling I have ever experienced in my life.

“Every time I close my eyes I envision a young girl crying for her mum because her head was in a pool of blood and her husband was trying to bring her round.”

Johnson’s children were still in the concert hall when the blast happened and were yesterday “very grateful to be alive”.

In the moments afterwards, many of those inside thought a balloon had popped or a speaker had blown.

The 21,000-capacity venue was clearing after a three-hour extravaganza, with many of the young crowd clutching pink balloons.

However, those closer describe a “massive bang” that floored them, killing 22, injuring 59 and leaving glass and metal nuts on the floor.

Homeless Chris Parker, who went to the venue to beg, said a woman in her 60s died in his arms, and told how he aided a young girl with “no legs”, wrapping her in a T-shirt from the merchandise stall.

He said: “I haven’t stopped crying. There were nuts and bolts all over the floor. People had holes in their back.”

The woman who died is said to have had head and leg injuries. Parker, 33, said: “She passed away in my arms. She was in her 60s and said she had been with her family.”

Teenager Ellie Ward told how her 64-year-old grandfather suffered a severed artery when he was caught by falling glass close to the merchandise stand.

The 17-year-old said: “He only realised what had happened when he felt the side of his head and it was bleeding.

“We heard a massive shudder. We knew something was wrong.”

Andy Holey said he was thrown “about 30 feet” by the blast as he waited to pick up his wife and daughter at the end of the concert, describing the scene as “carnage everywhere”.

Ryan Morrison, 19, went to the gig with friends and described how panic took hold of the crowds, saying: “It was one massive bang and then I saw smoke. I heard someone shout ‘bomb’ and then everyone started running.

“People were injured being trampled as they tried to get out.”

Oliver Jones, 17, had been at the concert with his 19-year-old sister and told how confusion and panic left fans unsure of where to turn. He said: “The bang echoed around the foyer of the arena and people started to run.

“I saw people running and screaming towards one direction and then many were turning around to run back the other way. Security was running out as well as the fans.”

Catherine Macfarlane was also amongst those trying to leave the hall when the bomb went off.

She said: “We were making our way out and when we were right by the door there was a massive explosion and everybody was screaming.

‘‘It was a huge explosion, you could feel it in your chest.

“It was chaotic. Everybody was running and screaming and just trying to get out of the area.”

Meanwhile, John Young said his family had a narrow escape, leaving early to beat traffic and being put off merchandise by queues.

He said: “If we’d delayed it by 20 seconds, God knows what would have happened.”