Unfortunately information covering each of the last 10 years is not readily available. However, I can confirm that since the last general election no staff have been directly employed on zero hour contracts in the Cabinet Office.
In 2008-09 seven individuals and in 2009-10 six individuals were indirectly employed through other companies on zero-hours contracts. In 2010-11, 2011-12 and 2012-13 the number of such individuals has been five or fewer. In line with the practice of previous Administrations exact numbers are not usually disclosed to protect individual privacy when the numbers are five or fewer.