The legalities of living polygamously vary from country. The map above shows where it is technically legal and illegal, and where it is legal only for Moslems and where it is illegal but tolerated.
In the European Union (EU) the marriages of Moslems entering who are already polygamously married (in their native countries, e.g. Pakistan) are recognised by law (but this varies from country to country). However, they may not technically contract further polygamous marriages while living in Europe. This provision does not apply to those practicing other religions or to those practicing no religion at all. We know of only one exception given to an atheist based on cultural grounds and that is in Sweden (see Articles #40 below) but that has never, as far as we know, since been repeated.
The HEM ministry has never given legal advice because this is not something we are expert in or have the time to do. One or two other Christian Polygamy ministries may be able to help you out in that area of interest.
The articles and links that follow only cover the legal question in very general terms.