Merinda - "I do not think that the tax situation makes much difference to the "level playing field". "
Oh yes it does. It makes a huge difference.
If I set up a coffee shop and have to pay tax on profit at UK corporate tax rates I have less profit to reinvest so I grow a lot slower than the big multinational. I could raise fresh capital on the stockmarket to help me grow quicker but my profits are lower so investors will give me less capital.
The problem is that Starbucks and others depend on stable countries like the UK for the profits they make.They enjoy the benefits of a sophisticated law abiding society in the UK, a good legal system, a financial system, low corruption, good infrastructire - but don't pay for any of it. They enjoy the benefits of trading in the UK but put little or nothing back other than employing people on minimum wage - which a tax paying UK company could also do.
I think the solution to this problem which is widespread among many companies, not just Starbucks, is to impose higher rates of taxes on property (ie business rates) and national insurance on employee wages. In other words impose tax on the things they can't move offshore.
Let me be clear, they are not doing anything illegal and they are entitled to manage their tax affairs efficiently but it is also the duty of HMRC and UK Govt to design a tax regime that cannot be avoided by multinationals and is a level playing field for all firms.