The rival bosses of the world’s two biggest ad groups met briefly on Thursday when they discussed how to shake up the annual festival, which critics say has lost its focus on creativity and become too driven by making money.
"We are considering what the alternatives are," Sorrell said, explaining he and Wren had bumped into each other by chance. "What I suggested to John is that we look at alternative locations."
Omnicom would not comment.
Sorrell said the leaders of the all the big six ad groups first discussed how to change Cannes Lions privately a year ago on the fringes of an event with Ban Ki-Moon, the United Nations secretary-general, when one of them suggested "an alternative conference". However, there has been no effort to move forward on that proposal since then.
The future of Cannes Lions has shot up the agenda, after Publicis Groupe said in a shock move earlier this week that it would pull out of next year’s festival and all other awards for 12 months.
Publicis Groupe is said to be under pressure from the French government to rethink its planned boycott because the Lions is a major contributor to the local economy in Cannes.
Sorrell played down the suggestion that WPP might follow Publicis Groupe, but pointed out: "If, for example, we were not here or Omnicom were not here, and we know Publicis is not going to be here next year, what’s the point of the [Cannes Lions] competition?"
However, he said a boycott would be a mistake. "The Publicis move reminded me a little bit of Havas’ boycott of YouTube," Sorrell said. "Boycotting something that’s important or significant doesn’t get you anywhere. Trying to reposition it or refashion it or re-do it gets you somewhere.
"The problem with the boycott is the creatives love this [festival] and quite rightly so. There’s nothing nicer than picking up a gong or a Grand Prix. Clients like it too."
Cannes Lions, which is owned by Ascential, has been an annual fixture for the ad industry for decades and most observers think it is highly unlikely that the festival would relocate. New York, London and Berlin have been mooted.
Sorrell insisted: "It’s something that should be considered. Is Cannes in June the right place?"
It is thought all of the big six ad groups could meet after Cannes to discuss a way forward.
Sorrell said Cannes Lions "has lost its focus" and "people are not focused on the [creative] work. It’s become too much about making money."
However, he said Ascential deserved credit for expanding Cannes Lions. "To be fair, it broadened its focus to take in creativity of a broader type and is to be congratulated on that," he said.
But he claimed "everyone that I’ve asked has questioned the cost".
Ascential declined to comment, although it is expected to talk about its future plans for Cannes Lions once this year’s festival is over.
Industry sources say the organisers of Cannes Lions had been privately talking to a number of senior attendees to gauge opinion, even before Publicis Groupe spoke out on Tuesday.