Colleagues have today paid tribute to the Southampton made killed in a Taliban suicide bombing in Afghanistan.
Del Singh, who previously worked for the executive office of the Deputy Prime Minister, was working as an international adviser supporting the Afghan Budget Department in Kabul at the time of the blast.
Colleagues have paid tribute to a ''professional, reliable and witty'' character who was a pro-Palestine supporter.
William Morrison, managing director of Adam Smith International, said: ''Del was skilled at drawing people together - his presence made meetings flow more smoothly, and helped difficult negotiations reach amicable conclusions.
''His professionalism, reliability, and irrepressible good humour made him well-known throughout the Budget Department and the close international community in Kabul.
"Del was the sort of person who was always welcome in any room or any discussion - it was impossible to be bored or out-of-sorts when Del was around.
''His constant stream of witty remarks and clever jokes could make anyone laugh.
"But his levity could only partly mask his deep commitment to the work he had chosen, including his lifelong dedication to the Palestinian cause, for which he spent much of his spare time doing volunteer work.''
Mr Singh's colleague, Malaysian advisor Gnana Nagarajah, was also killed in the incident.
He was described as possessing a ''razor-sharp mind, deep experience, and kind-heartedness''.
Mr Morrison said: ''It was impossible not to love him - for his generosity, which delighted in giving gifts to others and cooking elaborate meals for his friends; for his caring nature, which made him the sort of person who thought the best of everyone and always looked out for the welfare of others; and for his gregariousness, which led him to host parties and surround himself with friends.
''Gnana and Del had this in common: they were an unqualified pleasure to work with, to live with, and to spend time with. It was a profound privilege to have known and befriended them - their death is an enormous loss. We express our deepest condolences to their families and all our thoughts are with them at this terrible time.''