0.3p is an error of 0.02%. For every 1degC change in temperature the volume of fuel you get varies by .125%. So, if your fuel is at 15degC and then the next time you go it is at 16degC, you will get 0.125% less volume of fuel. In other words, the weather is making the amount you get 60 times a bigger error than the price you pay.
There's a campaign in some US states to get volume compensation made Law for fuel pumps. When Trading Standards measure they correct the amount back to the volume at 15degC to check that the pump is delivering the right amount of fuel.
Petrol stations aren't ripping you off, the weather is doing it 60 times more!! Sorry, to let facts get in the way of your sensational headline.
