Shareholders represented at the supermarket group's annual general meeting Friday voted about 57 percent in favour of Tesco's plan to extend the period during which leaving or retiring executives can exercise their share options.

The protest is the latest sign that investors are prepared to voice their displeasure publicly against company boards -- something they have been reluctant to do it the past -- particularly over pay.

Thursday, some 36 percent of Home Retail shareholders at the company's annual general meeting voted against the retailer's executive bonus scheme, with a further 7 percent abstaining.

Tesco more comfortably saw off a rebel resolution from Unite, Britain's biggest trade union, which was defeated 89 percent of the votes to 11 percent.

The resolution, supported by protestors wearing yellow chicken suits and waving placards outside the meeting, called on the company to do more to ensure the fair treatment of migrant workers at meat suppliers.

Earlier this week, Tesco came under fire from another union group, the UNI Tesco Global Union Alliance, which attacked it over its treatment of workers in Thailand, South Korea and the United States.

Tesco described the UNI's allegations as "a travesty" and "untrue" and the Usdaw union, which represents many of Tesco's staff in Britain, said they were not things it recognized in its dealings with the firm.

At 12:40 p.m., Tesco shares were up 0.1 percent at 350.7 pence, compared with a 0.4 percent decline in the DJ Stoxx European retail index

Next week, retailer Marks & Spencer faces a rebel resolution at a shareholder meeting which calls on Executive Chairman Stuart Rose to share power by appointing an independent chairman by July 2010.

(Writing by Mark Potter; editing by James Davey and Karen Foster)