Hopes are fading in a search and rescue operation at a block of flats gutted in a suspected arson attack that left one person dead and a number of others unaccounted for.

Superintendent Steve Raffield from Thames Valley Police told journalists near the scene in Reading Berkshire on Wednesday that it was “highly unlikely” that any further survivors would be found at Rowe Court.

The building in Grovelands Road has been so badly damaged by fire that it is unstable.

A 31-year-old man has been arrested on suspicion of murder and arson after the fatal blaze that broke out shortly before 3am on Wednesday.

Witnesses heard an explosion and some residents were forced to jump from the building to try to escape the fire.

Mr Raffield said: “We have been working alongside our partner agencies to do everything we can to find signs of life.

“Sadly it is highly unlikely we will find any further survivors in the building.”

Earlier witnesses described a woman jumping or falling from an upper floor.

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 – I know one lady jumped from a high floor.

“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.”

Four people have been treated in hospital while another seven received medical care from ambulance crews at the scene.

Doug Buchanan from the Royal Berkshire Fire and Rescue Service told journalists that firefighters had rescued one resident with a ladder, while another was talked to safety by a call handler.

He said: “Our firefighters were able to rescue one of the residents from the building using a ladder, and our emergency call handlers gave fire survival advice to a resident that led them to safety, getting out of the property.”

Michael, 50, who lives opposite the building and did not wish to give his full name, told the PA news agency that the fire broke out in the side of the building.

“I have a great view of the building and was woken at around 3am to all the commotion,” he said.

“I saw it pretty early on, the flames were coming from the side of the building and engulfed all the other flats and the roof.

“People were shouting and screaming – it was chaotic.”

The source of ignition of the fire is not yet clear.

Police said the incident is not being treated as terror-related and urged people to avoid the area, where road closures are in place.

Another man who lives near the scene, who did not want to be named, told the PA news agency: “I’ve never seen so many police and fire engines in my life.

“The building has been really badly damaged, parts of the roof have been torn off, windows are smashed and smoke has been coming out of it for hours.”

In a statement on Wednesday afternoon, Thames Valley Police pledged that emergency teams would “exhaust all our efforts to find signs of life”.

They advised anyone who is concerned about a loved one to make a report online here https://mipp.police.uk/operation/NATIONAL21Y05-PO1 or by calling 0800 051 6079 or 020 7126 7641 from outside the UK.