British security giant G4S, a guardian of sites worldwide including prisons, offices and Covid test-centres, is facing a takeover tussle, with suitors pledging to vastly improve its tarnished image.

For several months, the company employing 533,000 staff across 85 countries has been courted by smaller Canadian competitor GardaWorld.

An improved offer of ?3.7 billion ($4.9 billion, 4.0 billion euros) has yet to trigger an official response by G4S -- a company that in recent years has been caught up in scandals across the world.

British security group G4S was criticized for its management of the prison in Birmingham
British security group G4S was criticized for its management of the prison in Birmingham AFP / OLI SCARFF

While mostly linked to allegations of mistreatment by staff in the UK, the company has been accused also of mismanagement at the US military's Guantanamo prison camp and in the West Bank.

Should GardaWorld come out on top -- it faces a bidding battle with American rival Allied Universal -- its chief executive Stephan Cretier has promised to draw a line under its target's controversial past.

"Shareholders (of G4S) have a simple choice -- remain invested in a company which has consistently failed them and the wider community for so many years, or realise their investment in cash, at a significant and highly attractive premium," Cretier has said.

"Despite its past problems and uncertain future, we believe we can turn the business around."

A unit of G4S' global operations was the target of a 2018 attack in Afghanistan
A unit of G4S' global operations was the target of a 2018 attack in Afghanistan AFP / WAKIL KOHSAR

G4S has become an attractive buying opportunity after its share price hit a 16-year low earlier this year. Allied Universal has offered ?3.25 billion for the business.

Its value has slumped "due in the main part to the wider market turmoil caused by the pandemic and subsequent global recession, so an opportunity presented itself to any potential predator", said Russ Mould, analyst at stockbroker AJ Bell.

In 2012, G4S acknowledged that it did not have enough staff to ensure security for the  London Olympic Games
In 2012, G4S acknowledged that it did not have enough staff to ensure security for the London Olympic Games AFP / CARL COURT

"Buying G4S would consolidate the buyer's position in what is still a fragmented market, given the UK firm's global reach," he told AFP.

G4S attracted attention after American security group Brink's bought the majority of its cash-handling operations -- which physically transport notes on behalf of businesses -- leaving the British group to focus on its core operations.

In the UK, this includes providing security at four prisons, 21 test centres for Covid-19, and the Hinkley Point nuclear power plant that is under construction.

G4S also provids security at the Wimbledon tennis championships
G4S also provids security at the Wimbledon tennis championships AFP / Daniel LEAL-OLIVAS

G4S, with annual revenues of nearly ?8.0 billion and a large presence in the US and Asia, traces its origins back to 1901 in Denmark and sees itself as a company that makes "a difference by helping people to live and work in safe and secure environments", according to its website.

But the group has been beset by high-profile scandals, most recently in July when it agreed to pay ?44.4 million for overcharging the UK government on electronic tagging contracts.

Last year, the company's involvement in the British immigration and asylum sector was ended after the BBC filmed staff allegedly abusing detainees at a centre in England.

In 2018, the UK government took back control of security operations at Birmingham prison following riots and where inspectors found conditions to be "appalling".

The government had to intervene also in 2012 by drafting in army personnel when G4S failed to provide enough staff to cover security for the London Olympics.

The company's reputation has been hit by overseas events as well.

In 2014, it stopped providing security at an Israeli prison in the West Bank following pressure from human rights activists.

The same year, it sold a subsidiary that provided services at Guantanamo, again after allegations of possible mistreatment.

It has nonetheless won other contracts there since.

jbo-bcp/wai