Victims of the Grenfell Tower fire were “spitting out black tar” after inhaling smoke from the burning tower block, a nurse who treated patients at the scene has said.

At least 12 people died and 74 were rushed to six hospitals as the devastating blaze ripped through the 24-storey building in Latimer Road in west London.

The death toll is expected to rise as investigators trawl through the wreckage in the search for other victims in the tower’s 120 flats when the fire started just before 1am on Wednesday morning.

Nurse Simone Williams said she had treated victims outside the building, where people were “coming out shouting that it was too hot”, reported The Times.

“A lot of the injuries were smoke inhalation, people were spitting out black tar that had gone on their lungs,” Ms Williams, who works at University College Hospital, told the newspaper.

When alerted of the disaster, hospitals prepared treatments for cyanide poisoning, fearing toxins released by foam in old furniture in the fire may have been inhaled by the victims.

Dr Malcolm Tunnicliff, clinical director for emergency and acute care at King's College Hospital in south London, said the hospital had “lots of cyano kits – which contain the antidote to cyanide poisoning – ready and waiting to give people”.

The hospital dealt with 12 casualties from the fire, a mixture of children and adults, who arrived by 3.45am, said Dr Tunnicliff. Tests showed none of them had been poisoned, which he described as a “relief”.

Grenfell Tower continues to smoulder 24 hours after start of fire

However, all the patients had injuries caused by smoke inhalation, some of which were ”very serious“, with some patients suffering “critical injuries” to their airways and lungs, the doctor told The Guardian.

Smoke inhalation is the most frequent cause of death in indoor fires, and injuries caused by breathing in smoke often take a day or longer to become apparent. Heat can damage the lungs, gases can lead to suffocation and the smoke can also irritate the lungs and airways.

Dr Vinod Diwakar, medical director for NHS England in London, thanked staff who “have been pulling out all the stops in caring for the patients affected”.

Hospitals are continuting to treat patients, 18 of whom are in a critical condition.

The fire comes just over a week after NHS staff helped keep all 48 victims taken to hospital after the terrorist attack at London Bridge alive.

London Mayor Sadiq Khan praised the NHS's response to the attack, tweeting: ”Thank you to our amazing NHS staff for your world-class treatment of those injured in Saturday's horrific attack.“

Dr Tunnicliff said when he was alerted of a “major incident” by a phone call at 2.39am, he feared another terror attack could have taken place.

”My first fear was: is this another terror incident? Oh God, what's happened this time?“ he said.

Grenfell tower fire Show all 42 1 /42 Grenfell tower fire Grenfell tower fire Local residents watch as Grenfell Tower is engulfed by fire Getty Images Grenfell tower fire London Fire Brigade said there has been a number of fatalities from the blaze Rex Features Grenfell tower fire The fire was first reported in the early hours of Wednesday and continued into the morning Rex Features Grenfell tower fire A local resident sees the fire over the rooftops @Ebajgora Grenfell tower fire A firefighter reacts at the scene of the blaze Getty Images Grenfell tower fire Residents watch as the blaze continues Getty Images Grenfell tower fire More than 200 firefighters have been fighting the blaze PA Grenfell tower fire London Mayor Sadiq Khan has declared the fire a major incident Getty Images Grenfell tower fire Police and fire services attempted to evacuate the concrete block of flats Getty Images Grenfell tower fire A woman runs to assist paramedics working at the fire at the Grenfell Tower Getty Images Grenfell tower fire Smoke rises from the building after a huge fire engulfed the 24 story Grenfell Tower in Latimer Road, West London in the early hours of Wednesday morning Getty Images Grenfell tower fire Fire fighters tackle the 24-storey building in West London Getty Images Grenfell tower fire Ambulances are stationed nearby Getty Images Grenfell tower fire Paramedics arrive with oxygen Getty Images Grenfell tower fire Emergency services believe it will take some time to establish the cause of the fire Grenfell tower fire Tens of people have been taken to five different hospitals across London Getty Images Grenfell tower fire A man comforts a boy after the tower block was severely damaged Reuters Grenfell tower fire Firefighters stand amid debris in a childrens playground nearby Reuters Grenfell tower fire Firefighters are stationed at the building Getty Images Grenfell tower fire Smoke engulfs Grenfell tower Rex Features Grenfell tower fire Lots of people donating water, food and clothing to St Clement's church for the residents of Grenfell Tower in Latimer Road Samuel Osborne Grenfell tower fire A man speaks to a fire fighter after a huge fire engulfed the 24 story Grenfell Tower in Latimer Road, West London Getty Images Grenfell tower fire According to the London Fire Brigade (LFB), 40 fire engines and 200 firefighters are working to put out the blaze. Residents in the tower were evacuated and a number of people were treated for a range of injuries EPA Grenfell tower fire A resident of Grenfell Tower is trapped as smoke billows from the window after a fire engulfed the building Getty Images Grenfell tower fire Members of the emergency services work at the scene of a huge blaze which engulfed Grenfell Tower, a residential tower block in Latimer Road Getty Images Grenfell tower fire According to the London Fire Brigade (LFB), 40 fire engines and 200 firefighters are working to put out the blaze EPA Grenfell tower fire Fire fighters tackle the building after a huge fire engulfed the 24 story Grenfell Tower in Latimer Road, West London Getty Images Grenfell tower fire The burnt facade of Grenfell Tower, the night after the fire in Latimer Road, West London REUTERS/Neil Hall Grenfell tower fire Local residents gather at a community centre near Grenfell Tower in Latimer Road REUTERS/Toby Melville Grenfell tower fire A resident in a nearby building watches smoke rise from Grenfell Tower in Latimer Road, West London AP Grenfell tower fire Police and rescue services operate near the fire at Grenfell Tower, a 24-storey apartment block in Latimer Road EPA Grenfell tower fire A man stands amid debris on the A40 after a serious fire in a tower block at Latimer Road in West London REUTERS/Toby Melville Grenfell tower fire A view of the empty A40 highway after it was closed in both directions, due to the proximity of the fire at Grenfell Tower block in Latimer Road EPA Grenfell tower fire Smoke rises from the building after a huge fire engulfed the 24 storey residential Grenfell Tower block in Latimer Road, West London Getty Images Grenfell tower fire Bodies are removed from the scene after a fire engulfed the 24-storey Grenfell Tower in west London Rick Findler/PA Wire Grenfell tower fire Bodies are removed from the scene after a fire engulfed the 24-storey Grenfell Tower in west London Rick Findler/PA Wire Grenfell tower fire Provisions on tables at the Westway Sports Centre close to the scene after a fire engulfed the 24-storey Grenfell Tower in west London Jack Hardy/PA Grenfell tower fire Beds are laid out in the Westway Sports Centre close to the scene after a fire engulfed the 24-storey Grenfell Tower in west London Jack Hardy/PA Wire Grenfell tower fire A pile of donated clothes, sleeping bags and water lie next to a police cordon near the burning the 24 storey residential Grenfell Tower block in Latimer Road, West London Getty Images Grenfell tower fire Signs asking for donations are seen outside the Notting Hill methodist Chruch Getty Images Grenfell tower fire Smoke rises from the building after a huge fire engulfed the 24 storey residential Grenfell Tower block in Latimer Road, West London Getty Images Grenfell tower fire A man is rescued by fire fighters after a huge fire engulfed the 24 storey residential Grenfell Tower block in Latimer Road, West London Getty

More than 160,000 fires were attended by emergency services in England in 2015-16. House fires were most likely to be caused by cooking and electrical appliances, while fires caused by cigarettes and other smoking materials led to the highest number of fatalities.

According to government statistics, 89 per cent of households have a working smoke alarm, up from 76 per cent in 2001.