The salary bill for ministers’ special advisers has risen by £1m in the last year, according to official figures.
So-called “Spads” are appointed by ministers to provide political advice over and above the impartial work carried out by civil servants.
The Cabinet Office put the increase down to the “unusual” pressures caused by coalition government.
But Labour said David Cameron’s pre-election promise to limit the number of special advisers was in “tatters”.
A leap from 85 to 98 in the number of special advisers – who work directly to ministers and often speak for them – contributed to a 16% rise in the total wage bill in 2012-13.