I do not know the details of the Vodafone case and haven't got time to find it out. I am also not in favour of a tax system that focuses more on collection from individuals than corporates. However, I am a little bemused by the concept that any company has a obligation, moral or otherswise, to pay anything other than the minimum legal amount of tax. What company has, as part of its strategy, an objective to maximise its tax rate?
Companies have their customers, their employees and their shareholders to satisfy? If any of those parties feels that the company is paying insufficient tax then they can protest - boycott products, leave, sell the shares/vote at AGM etc. Beyond that, I am not sure what else can be done.
Of course, if the legislation is wrong and/or Vodafone is deliberately evading tax, then that is another stroy.