Talk PR founder Jane Boardman said she felt an 'ethical responsibility' to continue work on the account, despite the business airline suspending operations last week.
She added that it would be 'churlish' for the agency to abandon Silverjet, despite the client's inability to pay for services.
'We're going to lose money on this, but we've known for a while that there have been challenges,' said Boardman. 'We feel incredibly proud of what PR has done for the brand. We'd like nothing more than for someone to rescue Silverjet.'
Silverjet launched in 2007 to great fanfare, billed as 'the UK's first business-only airline' (PR Week, 19 September 2007).
CEO Lawrence Hunt announced on 30 May that the company would suspend operations due to a lack of funding and that he was looking for new investors.
The Hogarth Partnership had been retained for the airline's financial PR but has now stopped working.
Smithfield is working on comms for Begbies Traynor, the corporate rescue outfit appointed as joint administrators for Silverjet.