The Metropolitan Police has spent £113m on protecting the Royal Family, ex-prime ministers and other VIPs in the past year, a total of £310,000 a day.
The money was spent on armed bodyguards who accompany those considered to be at risk, as well as patrols outside royal buildings and embassies.
The figure for 2009/10 was 11% lower than the previous 12-month period.
But Jenny Jones, a member of the Metropolitan Police Authority, said it was "indefensible" to spend so much.
"The government has to act quickly to cut the number of people protected, to show they care more about policing for ordinary people, not just the privileged," the Green Party politician said.
Scotland Yard has confirmed the Queen, the Prince of Wales and Prime Minister David Cameron receive protection.
Others who are known to be shadowed include former prime ministers such as Tony Blair and Sir John Major, and former Pakistan president Pervez Musharraf.
The list is continually reviewed by senior police officers, civil servants and diplomatic representatives.
Police forces in England and Wales are given funding each year for protection purposes.
But Met Commissioner Sir Paul Stephenson has repeatedly asked the Home Office for more money, saying the sum his force received from Whitehall was insufficient to meet the costs.
As a result, part of London's council tax bills is allocated to the police to cover these responsibilities.
Scotland Yard and the Home Office declined to comment on the figures.