A mother and three children have died after being found in an upstairs bedroom during a house fire in Bootle, Merseyside, fire officials have confirmed.

Merseyside Fire and Rescue Service and Merseyside Police have launched a joint investigation into the cause of the blaze at the semi-detached property on Stone Square, which broke out at approximately 3.45am.

Eight firefighters entered the property to conduct searches and actively tackle the flames, where they discovered four people upstairs showing no signs of life. The North West Ambulance Service's hazardous area response team attended the scene and confirmed the four fatalities.

A fifth casualty, who was outside the address when emergency crews arrived, has been taken to hospital.

The fire service confirmed the main blaze has now been extinguished, with crews damping down the area. At the height of the incident, six fire engines were in attendance. Chief Fire Officer Nick Searle previously described the fire as "intense" and said it "spread very rapidly" through the home.

Kevin Longshaw, area manager for Merseyside Fire and Rescue Service, said: "This is a devastating incident, and our thoughts are very much with the family and friends of those who have lost their lives and been injured. We will work closely with relevant colleagues to ascertain the cause of the fire, but in the immediate term, we again extend our sincere condolences to those affected by this tragic incident."

Police cordoned off Stone Square while the emergency operation took place, with fire officers speaking to nearby residents throughout the morning.

People living nearby described waking to sirens and commotion. One neighbour, who did not want to be named, said: "We all came out on the front and we could see smoke coming over from the houses. The sirens woke me up and there were fire engines in the street."

Another local woman said: "I heard shouting in the early hours but I just thought someone was having an argument, then I came downstairs and saw all the fire engines."

Bootle is a port town situated in the Metropolitan Borough of Sefton, positioned along the banks of the River Mersey roughly three miles north of Liverpool city centre. The area grew rapidly during the 19th century through the expansion of the Liverpool Docks and its Irish Sea links, and is known as the birthplace of former Liverpool FC captain Jamie Carragher, as well as Steve McManaman and Roy Evans.

What we do not know yet is the specific cause of the fire, the formal identities of the victims, or the medical condition of the person taken to hospital. I'll be following this one — check back for updates.