While I agree that the price of alcohol has been getting increasingly high over the past few years, it is nevertheless still a luxury item.
Petrol I can understand people complaining about, since for most, travelling by car to get to work etc is a necessity, and without transport, they wouldn't have a job etc.
There is no basic human right that we should be able to afford alcohol though. You might as well petition the government that 3D TVs are too expensive and they should cut tax on those so you can afford one. Because you want one.
Having said that, i do think there are better ways for them to raise money, and better things to tax, but that's what you get with a Conservative government.