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

A man and woman in their 30s, an 11-year-old girl and a three-year-old boy were found in the property.

Officers were called to the house in Bedfont, Hounslow, at around 3.12pm on Friday 16 June, after being alerted by a person concerned about the occupants welfare.

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."