Founded 40 years ago, HPF provides mechanical and electrical engineering design, and energy and sustainability consulting services. The UK-based business, which has operations in India and Australia, has made three acquisitions in the past ten years and plans more.

In January 2009, the consultancy bought building services firm ATCO Consulting in Glasgow in a move to expand its presence in Scotland. ATCO provides building services engineering and project management, and is an accredited low carbon consultant.

HPF chairman Paul Flatt says the growth capital will be used to hire more highly skilled staff and help the company pursue its ‘next phase of growth’ both in the UK and internationally.

Daniel Smith, who led the investment in HPF on behalf of ISIS, adds: ‘With its relentless focus on customer service and ambition for international growth, HPF possesses many of the attributes that we associate with a great business.’