The police are currently seeking any information about man and his teenage sister, believed to have travelled to Egypt.
Moses Phillips, 23, and Beatrice Anita Phillips, now 16, were last seen by their mother at their Isleworth home at about 10:00hrs on Thursday, 24 April.
Beatrice suffers from Bi-Polar and requires regular medication. When their mother was unable to locate her, she reported her daughter missing at about 21:00hrs that same day.
Shortly after 21:00hrs, Moses sent a text to his mother to say that he and Beatrice were in Cairo.
Enquiries made by officers established that the siblings boarded a flight from Heathrow Airport on Thursday, 24 April. That flight landed in Cairo at about 21:00hrs.
Due to Beatrice’s young age, vulnerability and the fact that Moses does not have parental responsibility for her, officers must consider if Moses took his sister without her full consent.
On Friday, 25 April, Beatrice made a call to her mother, however nothing has been heard from either Beatrice or Moses since that date.
Detectives from Hounslow CID continue to investigate this as a missing person’s enquiry and have contacted the Egyptian authorities as part of their enquiries to locate Beatrice.
Detective Chief Inspector Sarah Pearce, Hounslow Borough, said: “We would like to appeal to anyone who may have any information – no matter how small – about Beatrice and Moses and their current whereabouts.
“Beatrice was only 15 years old when she went missing and we are particularly concerned for her, as she does not have with her, or access to medication she needs to stay well.
“The whole family is distraught and desperate to hear from them or hear from anyone in the UK or in Egypt who can shed any light on where they could be.
“We do not know why Moses took his sister with him as he did not have permission to do so and is fully aware of Beatrice’s medical needs.
“I would also like to take this opportunity to appeal directly to Moses and Beatrice: Please get in touch and let us know you are well. The number to call from outside the UK is 044 20 8247 6650, or please make yourselves known to the Egyptian authorities.”
Police are asking anyone with information to contact them on 101 if calling from the UK. To remain anonymous, call Crimestoppers on 0800 555 111 or text Missing People on 116000 or visit their website www.missingpeople.org.uk . If calling from outside the UK, call 0044 20 8247 6650.