Fire chiefs have defended their response to a huge house fire in Sheerness after it emerged no back-up crews were available.

Members of the public were concerned at the length of time it took for extra firefighters to arrive at the scene of the blaze, which is being treated as arson, to support the Sheppey team.

No on-call fire cover on the Island resulted in bystanders having to rescue people from the back of the building, while the professionals were saving a man who had climbed out the front.

Firefighters said it took around 12 minutes for another fire engine to arrive.

It comes as two young people continue to fight for their lives today after others were saved in a dramatic rescue.

Steve Jeffery, Kent Fire and Rescue Service area manager, said: "The on-call appliances for Sheppey and Eastchurch were not crewed at the time of this incident, as is standard for the crewing model for this area.

"Not all of our on-call stations are available all of the time - that depends on local availability of our part-time firefighters who often have other jobs and risk in particular areas.

"However, we ensure that we always have emergency cover across the county by making sure that engines are available and moved to ensure an adequate spread.

"This was the case in this incident, where the day-crewed engine arrived from Sheppey in just four minutes and the crew did an excellent job in rescuing those affected by the fire."

Kent Police confirmed detectives believe the blaze at a block of flats in Sheerness was started deliberately.

Two people in their 20s remain in hospital with life-threatening injuries today after fire engulfed the former pub on Tuesday afternoon.

A man thought to be 25 is in a critical but stable condition with broken ribs, a broken pelvis, punctured lung and a broken leg after leaping from the burning building.

And a woman, believed to be 21, is also in hospital after suffering burns to her back and windpipe. She is thought to have fallen from the building after losing her footing.

Fire spread through the roof of the former Glass House building in Marine Parade, at the corner of Richmond Street, at around 3.30pm.

The two people who fell from the top floor of the four-storey building were airlifted to London hospitals.

A further three others managed to flee the flames seen gripping the burning building.

A man was rescued by firefighters using a ladder, before being treated for breathing in smoke, and heroic members of the public saved mother Sam Hicks and her young children with a ladder at the back of the building.

Tony Fox, watch manager at Sheppey station, praised the members of the public for rescuing the trio.

He said: "I really cannot praise the public enough for what they did on that shout. Especially when you consider our second pump arrived about 12 minutes later."

Miss Hicks said she and her children Leo Bullock, five, and 16-month-old Rita Marie Bullock would not be alive if it were not for heroes including Reece Whiting.

The 28-year-old, who has lived in a flat in the building for just over a year with her partner Tommy Bullock, had just returned from the school run when the blaze broke out.

After hearing a fire alarm outside her front door, she rushed into her bedroom with the children and shouted for help as the smoke started coming up from underneath the window.

It was blowing into the room, so she grabbed her children and ran into their larger bedroom at the back of the house.

Video: Flames burst from the blazing building in Sheerness

Miss Hicks said: "I knew I couldn't go down the stairs because the smoke was thick and I wouldn't have tried with my kids.

"Smoke was in the front room by the time I moved to the kids' bedroom. I got them both up on the window ledge and I was just screaming for help."

She said there were about 20 people in the garden and she was shouting "get a ladder" when Mr Whiting came and rescued them all.

"I was panicking and they were all telling me to calm down," she added. "I didn't even gasp for breath - I just got to the bottom and wanted my kids.

"I felt trapped and I will never go in a flat again. I had visions of the building collapsing and keep on seeing my kids and me at the window..." - fire victim Sam Hicks

"I felt trapped and I will never go in a flat again. I had visions of the building collapsing and keep on seeing my kids and me at the window.

"We've lost everything - birth certificates and my partner's mum's ashes were in there.

"It was so quick - it happened within three minutes because there was nothing when I got home.

"I really don't think me and my kids would be here if it wasn't for that man."

Courageous Mr Whiting, 21, said he ran to the scene when he saw smoke coming out of the window.

He said: "I saw two men running around with ladders getting it up to the third floor window and trying to get it up.

"I said, 'You are taking too long, literally, you've got five minutes'.

"I was just thinking of them two babies' lives and the mum's. Basically I need to get them down.

"I've got a son, he was there in my head, but then I was thinking of the other two babies' lives.

Mr Whiting added: "The mum was only small, she was clinging on to me and shaking. I thought the ladder was going to fall because she was shaking so much.

"Afterwards she just gave me a cuddle and said thanks very much."

See more video from the scene below

Among those to help one of the women was Lynda Punyer.

She said: "I managed to hopefully help save somebody. A lady was brought out and wasn't breathing too clever. She had two little kiddies with her.

"I got her breathing and helped her until the ambulance arrived. That's all I could do.

"I've just got this horrible vision of these people still jumping out of the windows."

The road was still closed this morning and a cordon remained around the fire-ravaged building, whose roof has been left a shell.

Kent Police confirmed confirmed the fire in being treated as arson.

DI Lee Whitehead, who is investigating the blaze, said: "We remain in consultation with Kent Fire and Rescue Service and other specialists. At this stage we believe this fire may have been stated deliberately.

"I am keen to hear from anyone who may have seen anything suspicious, such as someone outside the front of the property, before the fire broke out. I would also ask anyone living nearby who has experienced a fire recently that they may not have reported to come forward.

"Currently we are treating this as arson and a man and a woman remain in a life-threatening condition in hospital.

"Their injuries are severe and I would welcome information from the public that will help us uncover exactly what has happened.

"Regardless of how insignificant people may feel their information would be I urge them to get in contact with police as soon as possible."

Picture gallery: Sheerness house fire

Around 30 firefighters, Kent Police officers and South East Coast Ambulance Service crews were called to the scene at 3.25pm yesterday.

An air ambulance landed on the beach nearby to help with the rescue and police evacuated families from nearby homes in Marine Parade.

Kent Fire and Rescue Service said there were six fire engines and a special height vehicle at the scene.

Horrific witness accounts emerged as flames were seen billowing out of the building.

Witness Kerry Standen said on Facebook: "As we drove past there was a man at the window shouting for help. He jumped in the end.

"I hope to dear God that the woman and man are OK. It was horrible!" - witness Kerry Standen

"Then a lady jumped out shortly after. It was horrific!!

"I had to carry on driving as I had my five-year-old in the car.

"As we were parked up just down the road the fire service turned up and saved the other man that was on the ledge.

"I hope to dear God that the woman and man are OK. It was horrible!"

Another witness said the scene she saw was "the worst thing I have ever seen in my life".

Jessica Cooke lives in Marine Parade on the opposite side to the blaze.

She said her builder dad was working in the room at the top of the house when he heard a commotion, looked outside and saw a woman jump from the flat.

She ran outside to see what was happening and there was a man standing on the ledge, who then climbed down the drain pipe.

The 20-year-old said: "It was a man and woman who came down - they were both airlifted to hospital.

"It was absolutely awful. It's the worst thing I have ever seen in my life.

"It was the worst thing to watch the man on the ledge.

"We didn't know what was going to happen."

Miss Cooke had heard there was trouble putting the fire out because the staircase has collapsed.

Lynda Punyer, 42, of Alma Street, Sheerness was with her daughter Shannon Denman, 15, when she was caught up in the heart of the disaster. Lynda said: "They brought some lady out not breathing - she was quite young and I stayed with her until the ambulance got there."I gave first aid and sat with her."I was there when the bloke jumped out of the window and I have never seen anything like it in my life. It was horrible."It was like a horror movie and scared the life out of me. It made me shake."A man was at the window saying get my kid, get my kid."We heard an explosion - a big bang - and when I saw all the fire at first I thought the school was alight."Shannon said she had heard a girl from her school, the nearby Isle of Sheppey Academy west site, had been there helping to get people out of the house and called the emergency services.

"It was like a horror movie and scared the life out of me.

"It made me shake" - Lynda Punyer

Julie Dewey, who lives in nearby James Street, saw the fire on the way back from the school run.

She said: "I have never seen anything like it.

"The flames are streaming out from the roof and there's just plumes of smoke."

Anyone with information about the fire is asked to phone Kent Police on 101 or Kent Crimestoppers, anonymously, on 0800 555111.

Video: Smoke pours into the sky amid a huge fire in Sheerness