Globalization skeptics argue that tax rates for capital haven't gone down very much as a result of increased capital mobility. Stories like this one suggest that they ought to focus their attention specifically on multinationals. Nick Cohen has a thoughtful take on the issue.
I am slightly more sympathetic to Dave Hartnett. If you are aiming to maximize the government's tax revenue, you probably would like the ability to negotiate with big multinational companies. Treating them the same as everyone else might just lead them to move elsewhere. On the other hand, there is a rules-versus-discretion issue: a reputation for being flexible on tax may lead other companies to demand special deals. Also, as Mr Cohen points out, the moral effects are not good.