The founding team brings together experience from client, brand consultancy and design businesses and claims to provide "truly independent and objective" brand advice for CEOs and marketing directors.
Allen, formerly CEO of Enterprise IG and The Brand Union, said: "Since I came into this industry in 1986 and built up Enterprise IG [now The Brand Union] for WPP in the 1990s, I have seen most of the well known established brand consultancies progressively acquired by the integrated marketing services groups.
"The result is that it is now really difficult for clients to access high level independent and objective advice. BrandPie will fill this market need."
He said that BrandPie is already working on consulting projects for a number of clients including 118 118, L'Occitane and The Juice Doctor, and is working internationally on projects in Ireland, Australia and Germany.
Partington has previously held positions as marketing director of Rowntree, board marketing director at Safeway and senior vice president of TXU Europe, which owned Eastern Electricity and Norweb.
He said: "We have experience of managing major brands and large businesses through at least two significant market downturns.
"Weak brands will not survive this recessionary period and so it is essential that brand owners actively manage rather than merely administer their brand assets, adapting to the changing market environment."
BrandPie has also acquired Widdup's business, Watershed Design.
Widdup, who was formerly the creative director of Sampson Tyrrell, said: "This is a great opportunity to get involved with a dynamic new business at a time when the market has never been more challenging. It's at times like this when creativity and ingenuity really matters."