The British use an imperial gallon, 80 oz instead of 64 like here. i.e; 4.5 litres instead of 3.86 litres.
That's why we celerbrate the 4th of July to get away from their silliness and silly spelling.
But then a pint of bitter there is 20 oz, not 16 oz like here and their bitter is much better then our micro brews so I guess it is a wash.
But as Kirk says, we all have a 85 litre tank and a litre is a liter no matter where your at....
English - Litre
American English - Liter
we just have to be different