The Supreme Court was until recently (2005 reformed under the Labour government) called the House of Lords. People have often confused this with the House of Lords that sit in Parliament. While many of the judges may sit there this once was a court that was overseen by the 12 Law Lords.
Since it has been restyled, the Supreme Court, similar to the American system, nothing much has changed but it is seen as a bit more open now some of the tradition has been shrugged off. Though you will see in most cases a reference to the House of Lords, it is simply the same as the Supreme Court.
The Court exists as the final and ultimate (excluding Europe) court in this country. Appeals will go no further and the Court has authority over all the lower courts in the country.