At least twelve people have died after a huge fire destroyed a tower block in west London with witnesses reporting residents caught in the flames.

The number of deaths could rise, with people who escaped the fire at the 24-storey Grenfell Tower in North Kensington speaking of others trapped and screaming for help, with some holding children from windows and others jumping from upper floors.

Commander Stuart Cundy of the Met Police said: "Sadly I can confirm that there are now 12 people that have died that we know of.

"This is going to be a long and complex recovery operation and I do anticipate that the number of fatalities will sadly increase beyond those 12."

London Fire Commissioner Dany Cotton said: "This is an unprecedented incident. In my 29 years of being a firefighter, I have never ever seen anything of this scale."

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A baby was caught by a member of the public after being dropped from the tower block, a witness said.

Samira Lamrani said she saw a woman try to save a baby by dropping it from a window "on the ninth or 10th floor" to waiting members of the public below.

She told the Press Association: "People were starting to appear at the windows, frantically banging and screaming.

"The windows were slightly ajar, a woman was gesturing that she was about to throw her baby and if somebody could catch her baby.

"Somebody did, a gentleman ran forward and managed to grab the baby."

She added: "I could see people from all angles, banging and screaming for help.

"Us members of the public were reassuring them, telling them we've done what we can and that we've phoned 999, but obviously the look on their face was death.

"My daughter's friend said she observed an adult who made some sort of homemade parachute and tried to lower himself out of the window.

"The more I looked up, floor upon floor. Endless numbers of people.

"Mainly the kids, because obviously their voices, with their high pitched voices - that will remain with me for a long time.

"I could hear them screaming for their lives."

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Pictures from the scene showed flames engulfing the block and a plume of smoke visible across the capital, while others showed residents looking out of windows in the block.

Residents who escaped the inferno complained there had been no fire alarm, with people relying on neighbours to wake them as the blaze spread.

They said official advice in the event of a fire had been to stay inside.

Mickey Paramasivan, who was in his seventh floor flat with his partner and child, said: "If we'd listened to them and stayed in the flat we'd have perished."

London Fire Brigade said the cause of the fire was still being investigated.

But several residents reported one man had said it started in his faulty fridge.

The leader of Kensington and Chelsea Borough Nick Paget-Brown said "several hundred" people would have been in the block when the fire broke out.

Actor and writer Tim Downie, who lives around 600 metres from the scene in Latimer Road, told the Press Association he feared the block could collapse.

He said: "It's horrendous. The whole building is engulfed in flames. It's gone. It's just a matter of time before this building collapses.

"It's the most terrifying thing I've ever seen. I just hope they have got everyone out.

"The first I knew was the noise of sirens, helicopters and shouting. I saw it engulfed in flames.

"People have been bringing water, clothes, anything they've got to help, out to the cordon.

"I have seen people coming out in their bedclothes - it's just very distressing."

Jody Martin said he got to the scene just as the first fire engine was arriving.

He told the BBC: "I watched one person falling out, I watched another woman holding her baby out the window... hearing screams, I was yelling everyone to get down and they were saying 'We can't leave our apartments, the smoke is too bad on the corridors'."

Fabio Bebber wrote on Twitter: "More screams for help as the fire spreads to another side of the building.

"We can see how quick the fire spreads via the external panels. It's unbearable hearing someone screaming for their lives at #grenfelltower."

George Clarke, who presents the Channel 4 TV show Amazing Spaces, told Radio 5 Live: "I was in bed and heard 'beep, beep, beep' and thought, 'I'll get up and run downstairs as quickly as I could'.

"I thought it might be a car alarm outside and saw the glow through the windows.

"I'm getting covered in ash, that's how bad it is. I'm 100 metres away and I'm absolutely covered in ash.

"It's so heartbreaking, I've seen someone flashing their torches at the top level and they obviously can't get out.

"The guys are doing an incredible job to try and get people out that building, but it's truly awful."

Shortly after 6am, London Ambulance Service said 30 people had been taken to five hospitals.

More than 200 firefighters were sent to tackle the blaze which was reported just before 1am on Wednesday.

Firefighters were on the scene within six minutes.

London Mayor Sadiq Khan tweeted: "Major incident declared at Grenfell Tower in Kensington" and urged people to follow London Fire Brigade on Twitter.

Former chancellor and now editor of the Evening Standard George Osborne tweeted: "Just seen this awful tower block fire near my home in W London. My prayers with those affected & heroes tackling it."

The cause of the fire was not known at this stage, London Fire Brigade said.

But residents said refurbishment work had recently been carried out with cladding on the outside of the structure and work on the gas supply to the flats.

A residents action group said their warnings about safety had fallen on "deaf ears".

A blog post from the Grenfell Action Group from November 2016 said "only a catastrophic event" would expose the concerns residents had.

The group said there was one entry and exit to Grenfell Tower during improvement works at the block and it had issues with evacuation procedures.

Following the fire, the group posted: "All our warnings fell on deaf ears and we predicted that a catastrophe like this was inevitable and just a matter of time."

An acrid column of smoke could be seen rising from the building on Wednesday.

The charred structure still had pockets of flame rising from several storeys as desperate efforts to bring the blaze under control continued.

Schoolboy Omar Kalam, 11, was standing anxiously at the emergency service cordon with father Walid, 44.

"My brother has friends and they live in there," he said. "I'm not sure if they are all right yet."

Parents from nearby Kensington Aldridge Academy, where Omar attends, had been told the school was closed, his father said.

The Metropolitan Police have set up a casualty bureau for anyone concerned about their friends and family on 0800 0961 233.

Commander Stuart Cundy, of the Metropolitan Police, said: "I can confirm there have been a number of fatalities and others receiving medical care. We will be soon making contact with next of kin."

The force said it was "likely to take some time before we are in a position to confirm the cause of the fire".

At 8.15am, London Ambulance Service said paramedics had taken more than 50 patients to five hospitals.

Anyone concerned for loved ones in the blaze can contact the Met Police casualty bureau on 0800 0961 233.

The NSPCC says children affected by the fire can call for support on 0800 1111.