The TaxPayers' Alliance (TPA) has identified cuts it says could save around £120 billion, enough to effectively wipe out the UK's budget deficit, without "closing a single hospital, firing a single teacher or disbanding a single regiment".
It recommends a number of major reforms to claw back cash in its Bumper Book of Government Waste, including shaving £53 billion off the pay and pensions packages of public sector workers – the amount it claims they are being overpaid compared to the private sector average.
The organisation also identifies a raft of lower level spending it suggests should be curbed to save taxpayers' cash, including the decision by one council to hire a "motivational magician" to boost staff morale.
"Nearly £120 billion of taxpayers' money was wasted or spent on useless projects by the Government in 2011-12," the report states.
"We have identified and listed hundreds of examples of spending by politicians and bureaucrats that can be cut without closing a single hospital, firing a single teacher or disbanding a single regiment."
The report, which is based on official statics, independent reports and media coverage, said £25 billion has been wasted through inefficient public sector procurement and poor use of outsourcing while £20.3 billion has been lost through public sector fraud.
Around £5 billion has been paid out in benefits to claimants with an income in excess of £100,000 and £1.2 billion was paid out in an annual subsidy to foreign farmers through the EU's Common Agricultural Policy.
The TPA suggests £2.9 billion could be saved by scrapping the Department for Business, Innovation and Skills and Department for Culture, Media and Sport and hiving off their essential functions to other departments.
It also questions the need for high spending on locum doctors, suggesting there could be far fewer now that GPs work out-of hours far less frequently than they used to.
The report warns every penny counts and includes a number of "small but ludicrous examples of wasteful spending in the public sector".
It claims £19,000 was spent by Cotswold Council on hiring a motivational magician to boost staff morale, reports that an Arts Council £95,000 grant was made in Brighton for a skip decorated with yellow lights and claims £12,000 was spent on a clothing allowance for "Geordie Armani" at Durham council.
Matthew Sinclair, chief executive of the TaxPayers' Alliance, said: "George Osborne must take the golden opportunity offered by the spending review to get the nation's finances under control and ease the burden on taxpayers.
"The latest Bumper Book of Government Waste shows that tens of billions of pounds are still wasted each year and there is an enormous amount of fat left in the public sector.
"If ministers do something about it, they can give taxpayers a better deal and still provide the front line services which people depend on the most.
"More money must be left in the pockets of struggling households who need it to support their own families and their own causes. They will get better value than any politician or bureaucrat."
The Cabinet Office insisted that work was well under way to make government "leaner".
A spokesman said: "This Government has accelerated its work tackling waste and the Cabinet Office recently announced achieved savings of £10bn over 2012/13.
"We are taking radical decisions to make Whitehall leaner and more efficient so Britain can compete in the global race, and we are pleased to see The TaxPayers' Alliance recognise this – but we agree there is more to do.
"We will push ahead with our programme of reforms to the Civil Service, stripping out waste and buying more goods and services centrally.
"Our reforms to public sector pensions will save the taxpayer billions and strike a fairer balance between the contributions by workers and the taxpayer, and we are working to reform outdated terms and conditions in the Civil Service.
"Hard-working taxpayers rightly expect their money to be spent wisely."