Investors group will vent its displeasure during AGM by voting against £4.6m remuneration package for chief executive

A substantial pay revolt will be mounted by shareholders at the annual general meeting of BP on Thursday following the board decision to give more than £4m remuneration to chief executive, Bob Dudley, despite a depressed stock price.

A group of investors will vote in protest against acceptance of this part of the company's remuneration report, emboldened by a negative recommendation from the shareholder advisory body Pirc.

BP is in the middle of a huge US court case over the Gulf of Mexico oil spill in 2010 that is still keeping its share price below that of rivals such as Shell and ExxonMobil.

Environmentalists and other representatives from the Gulf region are planning a noisy protest outside the ExCel building in London's Docklands but also hope to raise questions from the floor of the meeting.

The financial liabilities from the spill continue to dog BP but profits have bounced back, allowing Dudley to be awarded a $6.8m (£4.3m) payout including an "on-target" bonus of 150% of his basic $1.7m (£1.1m) salary.

At least 10% of the company's institutional shareholders are expected to follow the advice of Pirc, which sent out a research note arguing the bonus was "difficult to justify" given the lack of information about performance measures used.

"The remuneration structure has the potential to pay excessive variable remuneration and we note that [in 2011] this was the case," Pirc said. The "lack of verifiable performance metrics" led it to recommend shareholders oppose the remuneration report at BP's AGM on Thursday.

A BP spokesman said it did not recognise Pirc's analysis, adding: "Remuneration of directors is closely aligned with both the long-term performance of the company and the interests of shareholders."

Pay is not the only issue that will cause debate. A contingent of aggrieved Gulf business representatives and anti-tar-sand campaigners hope to raise difficult questions for the BP board.

One of those Gulf representatives, Bryan Parras, from Houston, claims he was prevented from entering the BP AGM in 2011.

He said: "This year, I will be attempting to deliver an even stronger message to the board: 'You claim that the spill has been cleaned up. This isn't true.' Oil is still impacting our communities, causing sickness, and triggering a collapse in fish stocks and local livelihoods. Many face overwhelming medical bills from illnesses associated with the spill and cleanup."

BP is still under attack despite spending more than $22bn (£13bn) on the spill, including paying at least $6.6bn (£4.1bn) in claims to individuals and businesses, about $1.4bn (£0.9bn) in claims and advances to government entities, and around $14bn (£8.8bn) for response efforts.

A company spokesman said: "BP's efforts to help restore the Gulf coast region have not only been significant, they are unprecedented."

Among those who will not be at the ExCel centre is Sir William Castell. BP's senior independent director and chairman of the safety committee saw 43% of shareholders vote against his re-election at the same event 12 months ago.

The City grandee, who is also chairman of the Wellcome Trust and on the board of General Electric, has decided to stand down as a BP non-executive and will not turn upon Thursday, his last day.

Carl-Henric Svanberg, BP chairman, also saw 15% of shareholders vote against him last year. But he has managed to retain the confidence of the majority of investors despite a very low profile in the immediate aftermath of the Macondo blowout, which claimed the lives of 11 oil workers.