In an interview with Campaign editor Claire Beale, in front of 200 people for industry charity Nabs, the man who has built the world’s largest marketing services group in the past quarter century, drew attention to its recruitment shortcomings.
WPP spent $9bn on its 142,000 people each year, but did not invest it "in a good way", he admitted.
"We go for the, forgive me for saying this, 'Jesus Christ phenomenon'," he said.
"How many times does somebody say: ‘I need to plug a hole, I need to get some talent, I want to hire this person, bring them in’, and three months later the person is dead … because they didn’t live up to the expectations.
"We don’t recruit people very well, we don’t assess them very well, we don’t give them feedback very well," he said.
"We’re trying very hard, we’re trying harder than we did a year ago, five years ago,10 years ago, but there is such a long way to go." he said, expressing a desire to get back to a time when the group’s creative agency JWT was the "university of advertising".
Sorrell mixed the self-criticism with barbs aimed elsewhere. Talking about setting up the WPP Fellowship training programme 10 years ago, he remarked: "Our biggest worry was that it would get copied by the industry and it hasn’t."
If the industry carried on filling its talent needs by "stealing people" it would create a "nuclear arms race" in which the price of talent was bid up unnecessarily, he claimed.
He said he and Omnicom chief executive John Wren agreed the ad industry’s biggest problem was that it stole talent, when they were on a panel with a third holding company leader who he initially did not name.
Sorrell accused the HR director employed by this "other" holding company of being "a professional nicker – all he does is go around the world writing emails to people, trying to steal talent".
He later said his fellow panellist "could have been Michael Roth [of Interpublic] or Maurice Levy [of Publicis]," before adding "and Maurice Levy wasn't there".