How much is a barrel of oil?
The worth of a barrel of US oil fell to less than nothing on Monday, the first time in history.
The value of West Texas Intermediate for delivery in June slumped to $ 6.50 at its worst, before recovering to settle at $ 11.57, down 43 percent.
Today it has risen to around $ 14 per barrel.
Will the price of petrol fall?
While the price of petrol is linked to the wholesale price of oil, it is driven by competition, not by the amount of oil there is in the world.
That means that what motorists pay is not directly linked to the price of crude oil.
Instead, suppliers control the prices they sell petrol at.
Crucially, a key factor affecting the price of fuel is that the biggest proportion of the money you hand over for a litre of petrol in the UK goes to the government in tax.
Fuel duty is charged at 57.95p per litre.
On top of that, you have to pay VAT at 20 percent on the cost of petrol.