His thesis examines the interaction between EU state aid rules and national tax measures, exploring, in particular, the extent to which EU state aid policy can serve as a tool against harmful tax competition between Member States. (europeanlawblog.eu)
A leading definition can be found in the 1998 OECD report «Harmful tax competition: an emerging global issue» (p. 22 and 23). (europeanlawblog.eu)
He added that if the UK did try to offer tax rulings or introduce tax incentives that were contrary to the EU's rules against unfair tax competition between members, it could actually put companies off due to worries about retaliation. (businessinsider.com)