David Cameron benefited from a little-known perk when he became Prime Minister in 2010, claiming £20,000 of his £142,500 salary tax free.
The 'prime ministerial expenses deduction' began in 1947, when it was set at £4,000, to cover costs incurred by the occupant of Number 10 in the course of official business.
After claiming the allowance in 2010/2011, Mr Cameron voluntarily declared extra taxable income to cancel out the perk in subsequent years before officials found a way to waive it entirely from 2014/2015.
A Downing Street source said by the time Sir John Major left office in 1997 the allowance stood at £8,000 but it rose to £20,000 during Tony Blair's term in Number 10.
Dennis Skinner was booted out after refusing to withdraw the comment he made to the Prime Minister in a debate over the tax row.
The Labour leader declared £1,850 in additional income, but was fined £100 for submitting his tax return a week late.
Chancellor George Osborne has released his tax return after the prime minister urged him to publish the records.