The Maastricht criteria for euro adoption are political instruments, not economically-vital measures, a respected economist has said.

Paul De Grauwe, a professor of international economics at the University of Leuven, has argued in an article written for VoxEU.org, an economics blog, that the criteria were ignored in 1998 so as to facilitate the eurozone's creation but were now stringently applied so as to slow its enlargement.

Some countries in central and eastern Europe are looking to