Visas
A visa is a document of authorization for a non-citizen to travel, enter, cross or remain in a particular country. A visa does not guarantee entry; this is the decision of the immigration officials of the country concerned.
If you are visiting for a short period of time, the immigration officials may ask you to present return tickets and evidence of funds to cover the visit.
If you plan to work in the UK and are a citizen of a European Economic Area (EAA) country, there are no visa or permit requirements. Immigrants from non-EAA countries will have to apply for a visa to work in the UK. When working in the UK an individual is expected to meet certain obligations, this includes paying taxes even if you are self-employed.
All immigrants wishing to work in the US must obtain a visa, and it can be a lengthy process involving many steps. As with US work permits an EB form must be submitted, these range from EB-1 to EB-4 depending on your experience and skills.
For non-immigrants who will be employed in a specialist field a H-1B document must be submitted. Specialist fields include; science, engineering, accounting and law. It can take a long time for an application to be processed and in some cases many years before a visa number is made available for the work visa which has been applied for.