The oil company head - who was forced to quit the company on Tuesday when it emerged that he had lied in court about a gay relationship - is also being advised by Brunswick partners David Yelland, former editor of The Sun, and Susan Gilchrist.
The agency is believed to have been working behind the scenes for Browne for two months.
Some in the PR community have questioned Browne and BP's handling of the case, wondering why the BP PR department didn't give a media outlet the story from Browne's angle. ‘It might have been painful and uncomfortable, but surely he'd have been better off getting ahead of the story,' said the media relations chief at another FTSE 100 company.
The head of a City PR agency told PRWeek that he didn't believe the saga would cause any damage to BP's reputation, even given the rumours over Browne's use of BP staff: ‘When you look at the reputational issues that BP is fighting - like the concerns over pollution in Alaska and safety across its US operations - this is small beer.' He added: ‘If BP is tying up communications' resources on this story, they need to untie them quickly.'
BP's head of press, Roddy Kennedy, has advised Lord Browne directly since the initial approach from the Mail on Sunday in January.