Murder detectives are heading the investigation, but no one else is currently being sought in connection with the incident, according to Scotland Yard.

Police were called to the property in Bedfont, Hounslow, at around 3.12pm on Friday 16 June, after concerns were raised about the occupants' welfare.

Officers forced their way into the flat and found the bodies of a man and woman in their 30s, an 11-year-old girl and a three-year-old boy.

Speaking at the scene, Chief Superintendent Sean Wilson said: "I believe we know who they are - four members of the same family - however, urgent enquiries are ongoing to locate and inform their next of kin and it would be inappropriate for me to name them at this time.

"Post-mortem examinations are now being arranged."

He added: "Our investigation is at a very early stage, and based on our initial inquiries, we are not currently seeking anybody else in connection with the incident.

"I know the shock and distress that this terrible incident will cause among the community in Hounslow and beyond.

"I can assure local people that specialist officers are working to establish exactly what happened and I will provide further information as soon as I can.

"I am also aware that this incident will be particularly upsetting for children, and I ask people to please be responsible about what they post on social media, including not naming or speculating as to the names of those who've died.

"There will be additional police officers in the area across the weekend, I urge anyone with information or concerns to speak with those officers."

A neighbour, who didn't want to be named, told Sky News that he came home from work at about 11pm and saw police officers coming out of the property.

"I saw four police officers, they looked upset, like they were crying, so I knew something bad had happened," he said.

He added that he saw police taking sheets into the property and felt quite disturbed. He said he didn't know the family but that it was still a shock because "nothing like that ever happens here".

Another neighbour told Sky News that he thought that the family was Polish, but that he didn't know them well.

"They seemed like a normal family," he said.