The change of agency follows a review procedure and competitive pitch, and will see BPPA tasked with developing 3i's corporate reputation within government.
BPPA managing director Peter Bingle said: 'We will be making sure the role of 3i and its standing as a venture capital company is understood within government and look to help build a constructive relationship between the two,' he said.
He added that the agency is 'getting up to speed' with 3i's business and setting out its lobbying strategy, before formally starting work at the start of May.
Bingle will head BBPA's work on the account, reporting to 3i corporate affairs director Liz Hewitt and Douwe Cosijn, also a director in the corporate affairs department.
3i is scheduled to reveal its annual results next month, which are expected to be broadly in line with analysts' expectations, despite a drop in activity in the mergers and acquisitions and tech markets.
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