A British parliamentary committee has criticised the way money is spent by the Royal Household.
The committee says Buckingham Palace should be opened to the public when the Queen is not in residence to raise more income.
The report from the House of Commons Public Accounts Committee raises some fundamental questions, the BBC reports.
Chairwoman Margaret Hodge said there was "huge scope for savings" on the annual £31m of taxpayer funds given to the Queen to spend on official duties.
It says the Royal Household needs to get better at managing its budgets over the longer term and accuses the Treasury of having failed adequately to review the household's financial planning.
While the committee praised the Royal Household for generating £11.6m last year - up from £6.7m in 2007/08 - it said more could be done.
Mrs Hodge said the Royal Household had escaped public sector austerity, only reducing spending by 5% in the past six years.
In response, the Palace has said that income has increased by more than 70 percent in the five years since 2008.