Dewhurst has axed City PR incumbent Bell Pottinger Communications in a move that marks the end of BP's spell on BNFL's retained agency roster.
Long-term incumbent Bell Pottinger Public Affairs lost the group's PA brief to Dewhurst's former PR agency Weber Shandwick just over two months ago (PRWeek, 19 April).
Dewhurst said BPC would continue on a project basis, handling ad hoc briefs, such as opinion-leader work.
Finsbury will now lead all financial and corporate communications for the group, reporting to Dewhurst, formerly the UK chief executive of what was then Shandwick International, alongside BNFL chairman Hugh Collum and chief executive Norman Askew.
Finsbury partner Rupert Younger leads the brief, with support from a team of two.
The agency's appointment follows a raft of changes at BNFL, including an in-house PR overhaul and creation of a corporate affairs division.
Dewhurst said Finsbury's appointment marks the final step in his review.
The agency will look to reposition BNFL among the investor community ahead of plans to part-privatise BNFL over the next three to four years, eventually followed by a stock market listing.
'We are looking to reposition BNFL as a viable business with the aim of a PPP in a few years,' said Dewhurst.
The Government is this week set to decide whether to create a Liabilities Management Agency (LMA) to help remove from BNFL's balance sheet some of the nuclear clean-up costs, which are believed to run up to £30bn.
'The proposed LMA would take the liabilities off our balance sheet and give us the chance to operate in a competitive environment,' added Dewhurst.
BNFL recently announced a restructure into two business groups: nuclear utilities and government services.