Nick Buckles pockets £16m as he finally quits G4S

Nick Buckles today unexpectedly quit as boss of FTSE 100 security giant G4S after having survived a string of corporate embarrassments including last year's Olympic security fiasco and a failed £5.2 billion takeover.

Buckles will leave the company where he has worked for almost three decades in 10 days, ahead of the AGM. He will depart with a pension and shares worth more than £16 million.

The 52-year-old will be replaced by Ashley Almanza, who as the security giant's current finance director has seen one of the corporate world's fastest promotions. The former BG Group finance boss has been working at G4S for less than three weeks.

G4S claimed that its search for a new finance boss had involved seeking "candidates with the experience and capabilities which would enable them to take on the chief executive role as part of the group's succession planning". Almanza might not have expected that to happen after just 20 days.

The timing of Buckles' departure surprised the City after major shareholders including Neil Woodford, investment manager at Invesco Perpetual, had repeatedly backed him. Buckles, pictured, joined G4S in 1985 and became chief executive in 2005, expanding the company into an international giant with 620,000 staff. However a profits warning earlier this month, which sent shares falling by nearly 15 per cent, may have been one piece of bad news too many. It followed Buckles' decision in late 2011 to launch a surprise £5.2 billion takeover of Danish cleaning firm ISS, which was thwarted after shareholders refused to swallow a £2 billion rights issue to pay for it. The failed deal saw G4S pay £50 million in fees, and chairman Alf Duch-Pedersen depart.

But Buckles kept his job, as he did throughout last summer's embarrassing security debacle at the Olympics, when two senior bosses left the firm after G4S admitted weeks before the opening ceremony that it had not hired enough security guards. The army was forced to step in and G4S was left with £88 million costs, sending its pre-tax profits down by a third to £175?million last year.

Buckles faced a grilling from MPs in Parliament, when he admitted presiding over a "humiliating shambles".