The deadline for bids to represent the academy expired at the end of January and it is thought that up to 20 agencies applied.
PLMR represented the academy until August 2014 and then afterwards on a not-for-profit, ad-hoc basis.
The agency was told that it could no longer represent the academy on a for-profit basis because its chief executive, Kevin Craig, sits on the academy’s board of governors.
PLMR told PRWeek that it had put in a bid for a contract on a not-for-profit basis, but in a U-turn this week, the agency said it was withdrawing its bid. Last week, the tender process was slammed by critics as "toxic" and "less than straightforward".
Elin Twigge, deputy managing director of PLMR, said: "We will not tolerate any mischievous suggestions that any part of the current comms tender, which has been run robustly, independently and arm’s length by Durand, has not been fair.
"To put an end to any further attempts by those who are background briefing to try to hijack and destabilise this important tender process – and indeed this amazing project – we have pulled out of it. Quite simply for us, the school comes first. That has always been our driver."