An investor revolt in Britain over executive compensation spread further Wednesday, with shareholders of WPP WPPGY -3.15% PLC giving an angry thumbs down to the 60% pay raise granted to Martin Sorrell, founder and CEO of the advertising conglomerate.

Shareholders voting in WPP's annual meeting opposed the company's executive compensation plan for 2011 by some 60%.

The compensation package for Mr. Sorrell had risen 60% in 2011—to £6.77 million, or $10.54 million, up from £4.23 million the prior year. When including compensation he earned over previous years but received only last year, he made £12.96 million.

Despite the anger over his pay, fewer than 2% of the votes opposed Mr. Sorrell's re-election.

Shareholder votes on executive pay aren't binding in the U.K., but such protest votes can send a strong signal to board members and management. And the U.K. government is consulting on plans to give investors more control over pay.

Louise Rouse, a campaigner from the U.K. responsible-investing group FairPensions, rebuked Jeffrey Rosen, the head of WPP's remuneration committee at the annual meeting in Dublin.

"Last year investors launched a very strong protest vote," she said. "I would have thought that would have alerted the board that there was significant disquiet, and again, it looks like you are facing another protest vote."

Last year, around 40% of votes were cast against the remuneration report.

In defending the 60% raise, Mr. Rosen said Mr. Sorrell's pay was benchmarked against international peer companies. He added, though, "If we take anything away from this, it is that we should have a more continuous program of dialogue with shareholders."

Mr. Rosen received a slap himself, with nearly 22% of votes opposing his reappointment.