The G4S AGM has been interrupted by protesters who hijacked the chairman's opening speech with a loud siren and angry chanting.
John Connolly was about five minutes into the meeting when a group of about 10 people reacted to a very loud horn by jumping up from their seats and rushing to the front of the room of shareholders.
The protesters' chants and shouts made reference to Jimmy Mubenga - an Angolan man who died while being deported by G4S guards.
The group was removed from the room in less than a minute.
The meeting resumed but was again interrupted by a lone protester who stood up and made accusations against G4S.
He too was removed from the room and the AGM got back under way.
Mr Mubenga, 46, became ill on a British Airways plane preparing to leave the airport after he was restrained by guards Terence Hughes, Stuart Tribelnig and Colin Kaler, in October 2010.
He later died in hospital, leaving behind his widow, Adrienne Makenda Kambana, and five children aged between one and 17.
In July last year, prosecutors said they would be taking no action against the three G4S staff over the death.
The group of protesters were spread out around the meeting room in Salters' Hall in the City of London as they sprung up from their seats.
The room, excluding the protesters, had more than 50 shareholders and members of the press.
When a protester sounded a horn, the activists drowned out Mr Connolly's speech and could be heard shouting "Jimmy Mubenga" and calling for justice for his death.
The shareholders and G4S panel looked on at the activists before they were removed from the room.
Men, who appeared to be security guards, acted quickly to get the protesters out.
A large group of protesters had gathered outside the building, and this group were also making reference to Mr Mubenga, and shouting out "justice".
Security giant G4S is no stranger to controversy and faced severe embarrassment over its botched handling of the Olympics security contract last year.
Chief executive Nick Buckles was pilloried by MPs over the fiasco, described as a "humiliating shambles for the company", before stepping down recently to be replaced by new boss Ashley Almanza - who was due to face shareholders for the first time today since his promotion.
Mr Almanza joined G4S as chief financial officer only last month.
Mr Buckles, who was paid a total of £1.2 million in 2012, walked away from the company with a year's salary of £830,000 and a pension allowance of £332,000.
The annual general meeting will be the first opportunity for investors to question senior executives in public over the episode.
Mr Buckles was instrumental in creating the G4S business through the merger of Securicor and the security businesses of Group 4 Falck in 2004.
But the end of his 28-year career was tarnished by the Olympics fiasco, when military personnel had to be drafted in to fill the gap left by G4S's failure to supply enough staff for the £284 million contract.
Chief operating officer David Taylor-Smith and Ian Horseman Sewell, who was head of global events, carried the can for the debacle while Mr Buckles initially stayed in his post.
But pressure intensified on him after a poor trading update earlier this month revealed margins had been squeezed by weak European markets and pricing pressure on its cash transportation arm in the UK and Ireland, which saw shares slump 13% in one day.
G4S is the largest employer on the London Stock Exchange with more than 620,000 staff worldwide.
Before the interruptions, Mr Connolly said: "In my first 12 months with the Group there has been a number of significant events."
He described the situation G4S found itself in before the Olympics as "difficult" and took the opportunity to praise former chief executive Nick Buckles saying he made a "massive contribution to the business".
It is thought the protesters may have bought shares in order to gain access to the meeting, or that they could have attended in place of a current shareholder.
The meeting resumed later only for executives to face awkward questions about its activities elsewhere and its approach to human rights.
Mr Almanza said the company took "human rights and ethical behaviour extremely seriously" and that the issue was "close to our hearts".
He added: "This company believes it has not breached international law."
One shareholder raised concerns about the company's controversial involvement in Israeli prisons and accused the board of complacency, as well as expressing her dismay at the "huge PR embarrassment" of London 2012.
Speaking after the AGM about the protest, Mr Almanza said: "I felt entirely comfortable facing the shareholders.
"One of the virtues of living in a democracy is that people are able to express their views. I think it's absolutely fine."
Mr Connolly, the chairman, added: "Their behaviour wasn't terrible. They made their point and allowed themselves to be taken out of the room. They didn't overdo it."
Reflecting on his time as G4S boss so far, Mr Almanza said he has seen a "lot of capable highly committed employees" which he said was "extremely reassuring".
Asked about how the company would improve after the year in which it faced a major backlash over London 2012, he said it would be "thoughtful about how we manage contracts".
A spokeswoman for City of London police said officers had not been called to the venue.