A Government department used chauffeur-driven cars more than 150 times to transport boxes containing documents for ministers, official figures show.
The Foreign Office (FCO) has disclosed it used the London Car Service for 151 journeys to move ministerial red boxes during 2013/14.
Ministers made 1,446 trips in the same period using the service, which is operated by FCO Services - an executive agency which is part of the department.
The service is largely used for transporting diplomatic bags, Queen's Messengers to courier documents to embassies and consulates and other classified material, according to the FCO.
Figures released to Parliament last year revealed the FCO, through FCO Services, spent £76,936 on the London Car Service in 2010/11, £148,850 in 2011/12 and £144,698 in 2012/13.
The London service is in addition to the Government Car Service - a fleet of cars provided to ministers and senior officials - which the FCO also has access to.
The number of journeys made in 2013/14 emerged following a written question from Labour's Lyn Brown.
She asked Government departments how many journeys their ministers had made using the Government Car Service and how many of the trips were solely for transporting red boxes.
Foreign Office Minister David Lidington, replying for his department, said: "Ministers do not make regular use of the Government Car Service and we do not record the times when it may be used by ministers.
"FCO Services, a trading fund of the FCO, has a small pool of vehicles and security cleared drivers (the London Car Service) which are used mainly for transporting Queen's Messengers, diplomatic bags and other classified material.
"As part of a long-standing arrangement the permanent under-secretary and other senior officials have been able to draw on this pool for official and operationally necessary travel and since 2010 FCO Ministers have also used the service.
"In the financial year 2013/14, 1,446 journeys were made by ministers using the London Car Service.
"A further 151 London Car Service journeys were made for the separate transportation of red boxes."
The Ministry of Justice replied that ministers made 331 journeys in 2013/14 using the Government service while there were 22 occasions when red boxes were moved.
Justice Minister Shailesh Vara added: " The total spend for the use of Government Car Service has reduced from £310,600 in 2008/09 to £28,739 in 2013/14, a reduction of 91%."
The Ministry of Defence replied that ministers and red boxes did not make any trips using the Government service.
Other departments said providing such information would incur "d isproportionate cost" or that it did not record journey details.