A 15-mile stretch between Baghdad airport and the city centre is said to be the world's most expensive taxi ride.
Baghdad's airport route has become a regular target for insurgents
Small convoys of armoured cars and Western gunmen charge about £2,750 ($5,108) for the perilous journey.
The route, known as the Qadisiyah Expressway, has become the scene of regular attacks and kidnappings by insurgents.
Security costs have soared in Iraq reflecting the escalating risks for foreign workers.
The high-speed drive costs four times more than the £670 Royal Jordanian charges for a one-way flight from London to Baghdad via Amman.
It equates to about £183 a mile compared to 25p a mile for the 2,540-mile flight on the only commercial airline flying to Baghdad.
It offers two daily 90-minute flights, although times are subject to changes and cancellations, depending on whether the airport is under mortar attack.
The airport is the hub of the US-led coalition's military activities, while the high-security "green zone" is the centre of civilian administration.
"You could jump in an Iraqi taxi with a gun and get there for $20," said one security contractor, quoted by the UK's Times newspaper.
But with kidnappings a daily occurrence and Westerners being sold to Islamist militant groups for about £150,000, he advised against it.
A few thousand pounds will afford you two cars and four Western ex-military bodyguards, usually American, South African or British, packing MP5 submachine guns, M16 rifles and/or AK47 assault rifles.
The client rides in one vehicle at speeds averaging 100 mph, while the other, called the "gun car", travels close-by, looking out for potential assailants.
Since the beginning of the resistance, this vital route has come under attack from car bombs, suicide attacks, snipers and rocket-propelled grenades.
Security in Iraq is now big business. At least 10% of each reconstruction project budget in Iraq goes on protection.