As part of his team's Kris Kringle, Mr Ngoc was presented with a plastic reindeer. "When you press its tail it gives you a chocolate dropping, and a play dough with handwritten words 'Luan's modelling kit'," the economist said. "I was shocked and very upset. "That really spoiled the joy of the division's Christmas lunch so I quit halfway through it. "I had many sleepless nights after that, and always felt heartbroken when going to work the following days."

Do you know more? Send your confidential tips to ps@canberratimes.com.au Things got worse when colleagues told Mr Ngoc that the anonymous joker might have been one of his bosses. "The problem is the present is from a Secret Santa so I do not know who gave it to me so that we can talk it over," the former Level 1 Executive said. "I discreetly asked people around and the only information I can get on a confidential basis is the present is from a person whose position is higher than me in the Australian Public Service hierarchy." After a break for Christmas and New Year, Mr Ngoc returned to work but could not shake the feeling that he had been targeted and things were never the same.

"When I returned to work, the bad feelings came back," he said. "Why should I be offended and why should my profession be offended by someone who I think would know very little about economic and financial modelling to have such a low regard for the profession?" When a round of redundancies came in June 2013, the economist says he put up his hand "with a heavy heart". "Now, 2014 Christmas is coming and ... I still cannot escape from the sad feelings that Secret Santa forced on me two years ago," Mr Ngoc said. He said his experience should act as a warning to public servants and other office workers that "harmless pranks" can have long-lasting effects on colleagues' feelings and even their careers.