Hague had asked his followers on Twitter to tweet the answer to a question: "What do you think is the biggest contribution UK foreign policy can make to the world?"
The winning entry was from Gopal Rao, who answered: "UK foreign policy should focus on emancipation of #girlsandwomen through enterprise, supported by vibrant #socent culture within UK. #meetFS."
The prize was to meet the Foreign Secretary and live tweet an event, according to a statement by The Foreign and Commonwealth Office (FCO).
PSVI was launched on May 29, 2012 by Hague. It aims to strengthen and support international efforts to respond to sexual violence in conflict - including by enhancing the capacity of countries, institutions, and communities to support survivors and end impunity for perpetrators.
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"Through social media politicians have opportunities to engage a wider group of people than ever before, and this was a perfect example of the value of this," he said.
"Seeing the passion and dedication both of the Foreign Secretary and his team was incredible. The building is imposing but the people I met in the FCO are friendly and welcoming. I hope digital diplomacy reaps rewards," Rao said.