There are many differing schemes and creative ideas to legally reduce tax burdens. I don’t say avoidance because it’s almost impossible to do that and remain at liberty. There is no moral obligation on anyone to pay high tax burdens.
People who rely on public empathy such as Jimmy Carr should however consider if it’s worthwhile for his image before entering into dodgy schemes such as K2.
Residence in tax havens such as Jersey or Monaco are another and if it’s legal and you keep to the rules why should it be considered immoral? What about Non-Doms? They legally avoid high taxation by paying a fixed penalty. Is that immoral or wrong? It’s the law and the country benefits by it.
In fact in my experience negotiation with the revenue usually brings a decent compromise and restful nights.