The Hogarth Partnership will 'ensure the message gets out that there are pension fund issues that need to be addressed when considering the future of Northern Rock', said Hogarth partner Nick Denton.
The trustees turned to agency backing after what they termed 'serious developments' over the past few months.
They want to make sure members of the 'Final Salary' section of the pension scheme are kept up-to-date on the changes, and are reassured that their money has been invested safely.
Hogarth is charged with maintaining a strong voice with Northern Rock's prospective bidders, Virgin and Olivant. It will also 'seek from them a commitment to provide the additional funding that is required'.
In April last year Hogarth was brought in to advise Sainsbury's pension fund holders as the supermarket entered possible sale talks (PRWeek, 13 April 2007).
At the time, private equity firms were mulling over a potential £11.4bn bid, and a promise of extra cash into the pension fund could have made or broken any deal.
The agency has also advised ICI, Tellent and Royal Mail pension funds.
Northern Rock entered a crisis late last year as a result of the US 'credit crunch'.
After the first UK 'bank run' for decades last year, in which thousands of customers queued to close their accounts, Northern Rock turned to Freud Communications (PRWeek, 28 September 2007).
This week, shares in the bank slumped 15 per cent on fears that it would soon be nationalised.