A sponsorship works one of two ways. A company can sponsor you financially. This means upon being hired you will be sent to a British University for schooling, or the company will pay you upon hire for your education. A sponsorship also works similar to an American internship to gain experience in the work place.
In England college works on levels. Depending on the degree, after basic education you must be sponsored by a company to gain experience. Once you complete a specified amount of work you can obtain certification.
A variety of British colleges place students with company sponsorships. This means that the program will find companies to place you with instead of seeking this placement on your own. The method guarantees the necessary sponsorship to complete your certification.