Mining giant Billiton has become the latest company hit by the wave of protest over bonuses paid to chiefs, a report said.

Rebel shareholders are set to vote against the appointment of non-executive directors in protest at plans to give chairman Brian Gilbertson a �6.5m cash and shares windfall, the Independent on Sunday said.

The package will be awarded following the completion of Billiton's �20bn merger with Australian rival BHP to create the world's second largest mining and metals company.

While the deal is not reported to have caused significant disquiet among Billiton shareholders, many investors are angry they have been denied a vote on the firm's executive pay guidelines, the newspaper said.

"There is a lot of concern about the pay package offered to Gilbertson and the way Billiton has steadfastly refused to allow shareholders a say on the package," a fund manager told the paper.

Mounting concern

The warning follows mounting concern among investors over awards to heads of firms such as Vodafone, United Business Media and Marks & Spencer.

Criticism has centred not so much on the level of awards, which many shareholders feel are necessary to ensure top quality management in UK firms, but on their payout clauses.

The decision last year by Vodafone to give chief executive Chris Gent a �10m cash and share bonus for pulling of the takeover of Mannesmann was attacked for coming too soon for the deal's wisdom to be assessed.

Similar criticisms dogged bonuses paid to Royal Bank of Scotland chiefs a month after winning a takeover battle for NatWest.

Marks & Spencer boss Luc Vandevelde last week waived a �816,000 bonus which he could, under contract clauses, have claimed for hitting restructuring targets.

M&S shareholders had questioned whether Mr Vandevelde should be eligible for such an award when he had failed to deliver improvements to the retailers' trading performance.