Your question is unclear. There has always been a fuel duty. The only thing that changes is the level of that duty. The actual level depends on the type of fuel and is currently:
50.35 pence per litre for ultra-low sulphur unleaded petrol/diesel
53.65 pence per litre for conventional unleaded petrol
56.94 pence per litre for conventional diesel
30.35 pence per litre for bio-diesel and bio ethanol
16.49 pence per kg for gas other than natural gas (LPG)
13.70 pence per kg for natural gas used as road fuel.
9.69 pence per litre for rebated gas oil (red diesel)
9.29 pence per litre for rebated fuel oil