What's morally dubious about not paying more taxes than required?
Tax justice is an incredibly difficult philosophical issue requiring genuine nuanced thought rather than black & white logic.
For instance by 'required' do you mean required by law or by fairness (broadly speaking ability to pay)?
Do you think it's fair for everyone to pay the same tax (actual total amount), or to share the same tax burden (same percentage of income)?
If it is morally right to pay no more tax than as required by law do you not see a moral issue where wealthy people can afford to pay expensive tax lawyers to lower their tax burden, but less wealthy people cannot?
The Jimmy Carr example is an interesting one, Jimmy Carr hired an accountant to deal with his taxes, the accountant said 'I'll make it so you have to pay as little tax as possible in a 100% legal way', Jimmy said 'OK', and left him to it. The accountant used the K2 scheme.
Here is broadly speaking how K2 tax avoidance scheme works :
UK earners 'quit' their job
They then sign new employment contracts with offshore shell companies
The offshore companies 'rehire' their new employee to the UK but take their earnings
The offshore company pays the employee a much lower salary each month, but 'loans' them several thousand pounds
These loans can be written down as tax liabilities, thus substantially reducing tax payable to the Government
When Mr Carr correctly realised that this is what is known in the trade as a 'cunts' trick' he quickly apologised and agreed to pay his fair share of Tax based on his ability to pay.
@Asaggynoodle : Why don't you hire a tax lawyer and use something like the K2 scheme to avoid Tax?