The word “practice” in the question refers to the lawsuit as there are no obstacles when it comes to getting employed in a foreign law firm or multinational companies. However, law graduates who get recruited by UK law firms have to pass the Qualified Lawyers Transfer Scheme (QTLS) during or after their teaching contract.
When it comes to practicing law, overseas, different countries require different qualifications for practice. For e.g. each United State has different admission criteria. Some may require you to earn a Juris Doctor from a law college accredited by American Bar Association (ABA). Others may allow you to Litigation without earning a local degree but your degree will be scrutinized by the American Bar Association as well. The United State also has provisions for unauthorized practice of law where paralegals are restrained from practicing law.
When it comes to United Kingdom (UK), a person can practice as a Barrister, Solicitor or executive at law whose matters are governed by their respective professional bodies and hence the qualifications may vary. But to become in general for any of these designations, a person needs to take the QTLS.
The difficulty comes when a person has acquired law under the common-law system and he wants to practice in a civil law country, but who restrains if heart takes!
Advocates in the United States need to pass the state bar exam before they can practice in an individual state of America. Each state sets its own rules about who can sit for the bar examination.
A small number of states will allow people with foreign law degrees to sit. Some states require a clutch of classes. Other states will require a new degree – either a Master of Laws (a degree generally designed for oversea lawyers and certain American law college graduates who wish to specialize in certain areas) or the JD, and a small number of states will solitary accept the JD.
If you plan on practicing in the United States, It is definitely worth doing your research for the states where you might need to be admitted to the bar council or association.