"The effectiveness of AstraZeneca's defence was never really tested as MPs and scientists rallied to its cause," Powell said.
"However, legitimate questions about protecting 'national interest' alongside shareholders' rights remain. Are the prime assets of UK plc up for sale to the highest bidder or should we review the criteria around the UK's world-class science base, as it is a huge driver of future growth and competitive advantage?
"There's no easy answer but the questions raised won't go away simply because Pfizer, at least for the time being, has. The answers will undoubtedly influence how corporate comms teams promote and defend clients, as they will investors' attitudes to the UK."
Cohn & Wolfe managing director of corporate affairs Andrew Escott said: "AstraZeneca has used many of the available public bargaining chips, from tapping into national pride to aligning with the corporate tax debate."
He said this morning's Today programme interview with AstraZeneca chairman Leif Johansson was "predictably helpful", setting out the case against Pfizer in most of the questions.
"What matters now is how the dealmakers talk to the shareholders," he added.
AstraZeneca's stance was welcomed by shadow business secretary Chuka Umunna, who said "financial engineering" was one of the primary motivations of Pfizer’s bid and the issue was "cited by the AstraZeneca board as one of the execution risks justifying rejection of the bid". He added: "Ultimately it is for the shareholders to determine."
David Cameron told the BBC that the Government was "neutral", but official-level engagement is understood to be continuing.
Reactions from AstraZeneca shareholders have been reported as mixed. Richard Morewood of Axa told ITV he was "very disappointed".
Richard Marwood, of Axa tells me "very disappointed" by AZ board "not in shareholders interests" and "very hard to do a deal from here"— Joel Hills (@ITVJoel) May 19, 2014
Now that AstraZenica has rejected Pfizer's "final bid" let us see how much of a "national champion" it is in the years ahead.— Andrew Neil (@afneil) May 19, 2014
We don't want to see the takeover of great British firms driven by financial engineering - we want them to be driven by long term investment— Chuka Umunna (@ChukaUmunna) May 19, 2014