Tax 'justice'

Justice is a very emotive issue. On a slightly philosophical bent, what is justice?
Unfortunately I have a job so can’t spend my days pondering this question.
In a very roundabout way, I’m talking about this:
http://www.labourlist.org/yougov_poll_shows_that_over_70_support_our_call_for_tax_justice
Now being a big ol’ (bearded) lefty, I like tax rises. I think a big state is sexy, that’s why I’m a lefty after all. SOO, we have ourselves a very unpopular Labour government and a financial recession which is arguably the most terrible thing since ever.
How about indulging in a nice bit of rich-bashing tax rises?
If this poll referred to above is accurate, then Labour could show that it hasn’t run out of ideas and is sticking to some of the lefty basics that it has left behind to the extent that its core vote is deserting it.
Now, I’d like to see some (maybe fiscally neutral) measures which would, for example, remove those on minimum wage from direct taxation. I’d like to see a budget where the poor pay less tax and the rich pay more. Now it would be very difficult to ensure that this was indeed fiscally neutral as you never quite know how much tax changes will raise until after.

Simplifying the tax system including unifying all the bands, income tax, NI etc., yes.
A top rate of tax, yes.
A new tax on bonuses, yes.
Action of evasion and avoidance and all of that, yes.
Better enforcement of the current tax laws and tightening of loopholes, yes.

So, when in doubt, tax the rich. I am the Bearded Socialist, and I approve of this sentiment.