It is rare enough that McDonald’s gets taught a lesson in marketing by Burger King, but that is what seems to have happened after its smaller rival suggested they merge their signature burgers for charity.

Burger King took out full-page ads in US papers suggesting that the best bits of the Whopper and the Big Mac be combined to create a McWhopper that would be sold for one day only in a franchise run jointly by the the two companies' employees. The proceeds would go to a not-for-profit organisation called Peace One Day, which, as the name suggests, promotes peace.

So far, so clever marketing stunt. But a less than sure-footed response from McDonald’s seems to have handed Burger King the bonus of the moral high ground.

McDonald's chose to respond by way of a somewhat dismissive Facebook post by its chief executive, Steve Easterbrook.

“We love the intention but think our two brands could do something bigger to make a difference,” he said before chiding Burger King for comparing their relationship to a war. It paled compared to the “real pain and suffering of war”, he said before noting “a simple phone call will do next time”.

Media experts are declaring victory for Burger King. "McDonald's could easily have reacted in a fun, cheeky and engaging way – turning the entire situation around. Yet they missed this opportunity. 1:0 to Burger King," observed one such expert who you have probably never heard of called Martin Lindstrom, according to NBC.