The Government has admitted that official cars can sometimes be used to take papers back to a minister's home, while the minister in question takes the Tube.
Since Prime Minister David Cameron's crackdown on chauffeur-driven cars shortly after coming into power, stories of these anomalies have begun to emerge.
At question time in the House of Lords, Labour's Lord Dubs sought confirmation on whether this does happen.
Earl Attlee, for the Government, admitted that this does occur, but explained it is to save ministers carrying around classified information.
He said: "The point is that sometimes the minister may be attending other meetings, other events, where he does not want to be carrying classified material so the classified material is taken straight from his department to his home."
Lord Attlee said the use of ministerial cars was permitted for official business such as driving news and reasonable home to office journeys, but stressed the Government's commitment to limiting their use.
"The number of ministers with allocated cars and drivers will be kept to a minimum," he said.
Lord Attlee said the cost of ministerial cars was 20009/10 in £11.2 million, a figure expected to reduce to £7.6 million in 2010/11 and to £5.6 million in 2011/12.
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