Ministers must do more to show taxpayers how they are spending their money, Parliament's financial watchdog has warned.
The influential Public Accounts Committee (PAC) has insisted there is currently no adequate approach for safeguarding value for money across Government departments.
A new transparency drive to allow MPs and the public to better scrutinise Government plans and performance is needed, the PAC report states.
The committee backed the creation of Single Department Plans (SDPs), which require Ministries to set out clear aims until 2020, but warned they have not made it easier to hold Government to account for spending.
"There is a considerable way to go before the taxpayer will be able to see in detail what their money is being spent on and how well it is being spent," the probe states.
The report notes that departmental information is often out of date, and "significant work" is needed "to address the deep-seated problems that prevent Government measuring performance and linking outcomes to funding - which is ultimately taxpayers' money".
PAC chairwoman and Labour MP Meg Hillier said: "Taxpayers have a right to know how well Government is spending their money.
"They have long deserved better than the information currently available to them - a serious shortcoming that has not been properly addressed by the introduction of Single Departmental Plans.
"Government internal plans offer a level of detail not available to taxpayers or Parliament, and indeed for some objectives, no indicators to measure progress are published in SDPs at all.
"Even basic information is out of date - an alarming fact that does nothing to instil confidence in what should be dynamic documents setting out a clear picture of the shifting priorities, objectives and spending of Government.
"This becomes still more important in turbulent times, and Brexit will be a true test of whether SDPs are fit for purpose.
"As Government considers our recommendations for improving planning and performance, we urge it to be far clearer with Parliament and the public about what it is doing - and how well it is doing it."
A Cabinet Office spokesman said: "We thank PAC for their report on the important task of managing government spending and performance.
"We will look closely at the recommendations made and will provide a full response shortly."