Reading fire: One dead and others unaccounted for in flats blaze
One person has died and several others remain unaccounted for following a fire at a four-storey block of flats.
Residents were seen leaping from the burning building in Rowe Court, Reading. One has described their "miracle" escape.
Four people were taken to hospital, while another seven were treated at the scene, the ambulance service said.
A 31-year-old Reading man has been arrested on suspicion of arson and murder. He remains in custody.
Thames Valley Police has set up a dedicated phone line for relatives and friends.
Speaking at a press conference, Supt Steve Raffield said: "We've been working alongside our partner agencies to do everything we can to find signs of life.
"Sadly, it's highly unlikely we'll find any further survivors in the building."
He added the block of flats was "unstable".
Roads surrounding Grovelands Road are shut and people have been urged to avoid the area.
Police said the fire, which started at about 03:00 GMT, was not being treated as terrorism related.
In a statement earlier posted on its Twitter account, the force said: "If you have any concerns, for loved ones, please try and contact them in the first instance."
It has since released details of an online portal and dedicated number which have been set up for anyone needing to report anyone as missing, or who has any information to report relating to the fire.
The phone number for UK calls is 0800 051 6079. For calls from outside the UK, contact +44 20 7126 7641.
The Royal Berkshire Fire and Rescue Service said its crews were on the scene within eight minutes of receiving the first 999 call in the early hours.
Assistant chief fire officer Doug Buchanan said they were faced with a "challenging situation".
At its height, 50 firefighters from across Berkshire and Oxfordshire were involved in tackling the blaze.
He said although the cause of the fire was believed to be arson, its source had yet to be found.
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Posting on Twitter, Police and Crime Commissioner for Thames Valley, Matthew Barber, described the incident as "tragic news".
Jason Brock, leader of Reading Borough Council paid tribute to the "swift response" of the emergency services.
"Our thoughts and prayers are with everyone affected by this horrific fire," he added.
Rev Dr Adam Carlill, vicar at nearby St George's Church, said the church had been providing facilities for emergency crews.
"I don't think this has hit home yet," he said.
We're just waiting to hear reports, but I'm certainly very concerned and worried about all the people down there who are unaccounted for.
"I'm just very concerned about the people who don't know what's going on and may be missing loved ones."
Grenfell NHS News, a unique NHS service set up for survivors, witnesses and the bereaved following London's Grenfell Tower fire in 2017, posted support details for anyone affected by the Reading fire or those who found the news "triggering".
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South Central Ambulance Service NHS Foundation Trust (SCAS) said its Hazardous Area Response Team and two critical care doctors were among those deployed to the scene, as well as six ambulance crews.
A man who lives in the block of flats told how he made a "desperate leap" after becoming trapped in the blaze.
He said: "I was woken up by an alarm and heard a loud explosion. I heard the people inside screaming and shouting - I think they were my neighbours.
"I opened the door of my flat and saw a big cloud of smoke - and saw that the exit was trapped.
"I landed okay but hurt my leg. I thought it was better to break my leg than die. I think it's a miracle how it all happened."
Tom Price, 40, who lives in a nearby building, said: "All I heard was a massive explosion and saw smoke billowing from the flats.
"People were leaping from their windows...There were screams and shouts and glass was being smashed.
"The flames went on for hours but the police and fire engines were here so quick."
Mags Cadger, who lives in a house overlooking the block of flats, said the sound of glass being broken woke her up.
"We heard breaking glass so we looked out, we saw firemen up a ladder breaking the windows of one of the flats and then it must have been about 10 to 15 minutes after that we started seeing the flames coming out the roof," she said.
She added: "You just feel for people in that kind of situation, it's horrible."
Elizabeth Dylewska said she was woken up by helicopters flying above her house.
"We couldn't sleep because it was very noisy and we knew something was going on," she said.
She added: "It's very sad, especially at Christmas."
At the scene
By Andre Rhoden-Paul, BBC South
As daylight broke, residents in the surrounding area woke up to the acrid smell of smoke in the air and a large convoy of emergency vehicles.
A wide cordon was placed across Grovelands Road.
But it was when you walked uphill in the surrounding roads that the extent of the damage was revealed.
The roof of the block of flats was gutted and charred, with beams showing and tiles missing - some dropping to the ground.
Fire fighters on an aerial ladder platform used hose reel jets to douse the property's upper floors.
Resident Valerie told BBC Radio Berkshire she was woken by "loads of flashing lights and the whole of Grovelands Road full with ambulances and emergency vehicles over at Rowe Court".
"It's a bit of a shock really," she added.
Another neighbour said his wife heard a "boom" around the time of the fire.
No further details have been released about the person who has died, or those who are injured or unaccounted for.
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