David Cameron gave some of his special advisers bumper pay rises just months before they were given generous severance packages, it has been reported.
The former prime minister upped the salary of some of his advisers, known as spads, by as much as £18,000, or up to 24%, according to analysis by Civil Service World.
The double digit hikes were ordered despite pay being capped at just 1% across the public sector.
Trade unions and taxpayer groups said the increases are "shameful" at a time when Government departments have faced cuts.
Dave Penman, general secretary of the FDA union, which represents senior officials, told Civil Service World: "It would seem hypocrisy knows no bounds from a prime minister who preached pay restraint and austerity to public servants and the public, whilst at the same time awarding double-digit pay rises to his special advisers."
He added: "It will be a further body blow to the morale of thousands of hard-working civil servants to learn that the very same special advisers who received enhanced redundancy terms from the outgoing prime minister also received pay rises of up to 24% in one year."
John O'Connell, chief executive of the TaxPayers' Alliance, said: "Taxpayers will be shocked at the size of these increases at a time of necessary spending restraint.
"While spads can help ministers implement their decisions it's important to strike a balance and deliver value for taxpayers. Politicians talk about bringing down the cost of politics but it's important to follow it up with action."
The revelations come just a month after it emerged that Mr Cameron overruled strongly worded civil service advice and boosted the golden goodbyes he gave his special advisers.
He ignored concerns raised by civil service chief executive John Manzoni to hand his staff an extra £282,000 in severance pay because of his resignation.
Seven out of 10 of the Downing Street advisers reappointed after last year's general election - and who therefore became entitled to bigger severance packages - received pay rises of up to 24% in 2015, according to Civil Service World.
This far outstripped the 2% average pay award across the private sector in 2015.
Adam Atashzai, one of the spads given an enhanced severance package, saw his salary increase from less than £58,200 in 2014 to £72,000 in 2015 - up 24%.
He was also awarded an MBE in Mr Cameron's resignation honours list.
Ameet Gill, former director of strategy, and Liz Sugg, former head of operations at No 10, both reportedly received pay rises of 23% - sending their salaries from £80,000 in 2014 to £98,000 in 2015.
Ms Sugg was given a life peerage in the wake of Mr Cameron's resignation.
And special adviser Kate Marley went from being on Pay Band 1 in 2014 which is capped at £54,121, to earning £65,000 in 2015, an increase of at least 20%, it was reported.
Daniel Korski, former deputy director of the No 10 policy unit, had a 16% pay increase from £80,000 in 2014 to £93,000 in 2015, it was reported.
Special adviser Nick Seddon, who was awarded an MBE, benefited from an 11% pay rise last year, with his salary increased to £88,000, Civil Service World said.
Other advisers and speechwriters including Max Chambers, Laura Trott, Richard Parr, Martha Varney, and Kate Shouesmith all enjoyed pay increases, according to the report.
And Frances Trivett, the political private secretary to the prime minister's chiefs of staff, progressed from being in a Pay Band capped at £40,352 a year, to Pay Band 1 in 2015 - capped at £52,999 a year.
Mark Serwotka, general secretary of the Public and Commercial Services union, told Civil Service World: "We believe that every civil servant deserves a decent pay rise. It is frankly shameful that David Cameron thinks that this should just apply to his close circle of political friends."
He added: "Our members will be rightly outraged by the double standards of a prime minister who richly rewards a privileged few, while ignoring the falling living standards of hundreds of thousands of dedicated civil servants."
A Cabinet Office spokeswoman said: "Decisions about special adviser salaries take into account various factors including the level of responsibility associated with a particular role and the background and experience of the individual concerned.
"These increases, which were agreed by the then prime minister, reflected changes to the scope and range of responsibility in the roles of a number of special advisers following their reappointment after the 2015 general election."