Hart has had a $36-million-a-year contract (80 per cent salaries) since 2010 and has not had a single serious incident in one of the most dangerous places on earth. Hart pays its 120 Australian operators in Kabul more than any other firm and hired only top-tier and highly trained former special-forces or infantry soldiers to protect diplomats.

Its professionalism has been widely acknowledged in emails and letters, including one earlier this year from Australian Ambassador in Kabul, Matt Anderson, following the visit of Foreign Minister Julie Bishop.

“Put simply, the visit would not have been a success without … Hart’s support.”

For the elite close personal protection specialists Aegis is offering a pay rate of $US280-a-day (taxed) compared to the $US550-a-day (tax free) paid by Hart.

“For that kind of money I would be better off coming home and being a labourer,” one operator who we will call ‘Jack’ said.

“The threat level in Kabul is growing every day and these companies keep under cutting.”

Less qualified static guards will take an even bigger pay cut, if they take work with Aegis, and will have to work nine weeks on and three off compared to eight on and four off with Hart.

Senior diplomats are said to be shocked and nervous following the cost based decision to sign a contract despite the lack of a single Australian operator.

‘Jack’ attended an Aegis recruiting session in Kabul where he heard senior Aegis staff describe the firm as a ‘private military company’.

That raised concerns about mercenaries in a company founded by notorious British mercenary Tim Spicer.

The former British Army officer was at the centre of the Sandline crisis in Papua New Guinea in early 1997 when he was hired to destroy rebel forces on the island of Bougainville.

DFAT said Mr Spicer had no “day-to-day” role in the running of Aegis.

Jack said a senior DFAT official at the briefing insisted that security waivers could be provided to foreign personnel.

“He also promised to help Aegis obtain tax free status for its new team members,” ‘Jack’ said.

DFAT did not respond to specific questions about these issues.

Australian National University security expert Clive Williams said the market for security staff was tight due to shrinking budgets especially in the chronically underfunded DFAT.

“It is all about the dollars and people have to get used to lower pay,” he said.

Mr Williams said companies might get away with paying lower wages, but they could not afford to drop physical security standards in a place like Kabul.

In a briefing note to Hart staff this week obtained by News Corp, Aegis said it was conscious that the daily pay rates represented a reduction to present pay.

“The rates being offered are also higher than diplomatic contracts being delivered in Kabul by our competitors,” it said.

A DFAT spokesman told News Corp that Aegis offered the best value for money with its $72.3 million bid over three years.

“In assessing tender bids, DFAT carefully considered quality indicators including: experience and training of personnel and the organisation; possession of required licenses and authorisations; lawful acquisition and use of equipment and weapons; compliance with the draft contract issued in the Request for Tender; and price,” the spokesman said.

Hart Australia managing director Sallie Stone said that during the past five years in Kabul, Hart had met every requirement and request from DFAT with professionalism and diligence.

“It was a team effort, and we are exceedingly proud of our personnel. Our job was to keep DFAT safe and our team of ex-Australian servicemen did that conscientiously,” she said.

Aegis would not respond to questions from News Corp and referred injuries to a PR company.