The World Health Organisation (WHO) has paid tribute to colleague Glenn Thomas who is one of nine Britons to have died onboard Malaysia Airlines flight MH17 on Thursday.
Thomas, 49, a former BBC journalist, was among around 100 AIDS experts who were travelling to Melbourne for the annual International AIDS Conference, due to begin on Sunday.
In a statement, WHO says: "Glenn will be remembered for his ready laugh and his passion for public health.
"He will be greatly missed by those who had the opportunity to know him and work with him. He leaves behind his partner Claudio and his twin sister, Tracey. Our deepest condolences go to his family, friends and colleagues at this time."
Tributes from colleagues are also appearing on social networks praising Thomas as a "wonderful person and a great professional".
Nine Britons, including two Newcastle United fans and a student from Leeds University, are now known to have died on board flight MH17 when it crashed in eastern Ukraine, Malaysia Airlines said today.
Officials from the airline say 298 people were on board the Boeing 777-200, which appears to have been shot down over the war-torn country yesterday while flying in restricted airspace travelling from Amsterdam to Kuala Lumpur.
All passengers are believed to have died in the crash. Among them were 154 Dutch passengers, 45 Malaysians, including 15 crew, 24 Australians, 12 Indonesians, four Germans, four Belgians, three Filipinos, one Canadian and one New Zealander.
Three infants are among the dead and the nationalities of 41 passengers have yet to be verified. New Zealand authorities have also confirmed that one of its nationals died in the crash, reports the BBC.
Flight MH17 was said by eyewitnesses to have "exploded" on Thursday afternoon after it was reportedly shot down by a ground-to-air missile.
The passenger jet crashed near the village of Grabovo in rebel-held territory close to the border with Russia.
The cause of Thursday's crash was not immediately clear but the area has seen heavy fighting recently between government troops and pro-Russia separatists, with rebels bragging about shooting down two Ukranian military jets in the region just one day earlier.