Theresa May is due to announce a freeze on fuel duty for the ninth year in a row during her speech at the Conservative Party conference.
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Chancellor Philip Hammond has said the duty freeze comes at a "significant cost to the Exchequer" but that the Government was easing the burden on families.
Here are answers to questions on fuel duty:
What is fuel duty and how much is it?
Fuel duty - as the name suggests - is a tax placed on most fuels, and has stood at 57.95p per litre since the March 2011 budget.
Is that the only tax on fuel?
Value Added Tax - currently at 20% - is then added to the total price at forecourts.
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How much does fuel duty bring in for the Treasury?
The Office for Budget Responsibility said it will bring in £28.2 billion in 2018-19, equivalent to £1,000 per household and 3.6% of all income.
How much of the cost of fuel is tax and how has it changed?
According to the RAC Foundation, 59.6% of the pump price of diesel and 61.2% of unleaded is made up of tax. The charity's data, which runs from 2004, shows this peaked at 77% for unleaded and 75.6% for diesel in that year, and reached a low of 52.9% for diesel and 57.1% for unleaded in 2008.