A question for an international lawyer rather than a bunch of parochial bookkeepers, I reckon, and a bit too general to be able to give specific answers to. But you should be able to open a European office without too much difficulty: it's the quid-pro-quo for letting all those horrid Europeans in to work here! However, I do believe one or two contributors to this site have worked in EU countries and may have some info to share.

The way I see it, if you run any business in another country, you must have a principal office address in that country where official documents can be delivered. You must also satisfy all of the rules and regulations regarding the operation and management of a business, which I imagine can best be found from the Country's embassy, consulate or representative office. You will have to obtain local licences (if any). You must observe employment laws - 40 hour weeks/10 hour days/minimum wage rates. You will need to register for local taxes, if only to get an exemption.

Your UK company must still satisfy all UK laws and obtain any authorisations, licences atc. necessary to be able to operate, adequate capital (PLCs and SEs have a minimum capital requirement), and, of course must have a registered address in the country it was incorporated in. You will be liable to UK taxes although you may be able to claim double taxation relief.

All these questions, and many others, will need to be given careful attention and I suggest you speak to experienced advisers before committing yourself.

Bon chance/Viel Erfolg/Veel geluk/Buona fortuna/ ...

Iain