What is the name of the British historical drama set in the early 20th Century with six TV series and two films?

The British historical drama that is set in the early 20th century, featuring six television series and two films, is "Downton Abbey." This series first aired in 2010 and quickly gained acclaim for its portrayal of the lives of the aristocratic Crawley family and their servants. It effectively encapsulates the social changes occurring in Britain during this period, including class dynamics and the impact of World War I and the subsequent Roaring Twenties.

The series is well-known for its attention to historical detail, complex characters, and engaging storylines, which have resonated with audiences both in the UK and internationally. The two films released further expanded the storyline and character arcs that were developed over the six seasons, contributing to the series' legacy as a significant piece of British television history.

The other options, while also popular British series, do not match the specific criteria given in the question. "The Crown" focuses on the reign of Queen Elizabeth II, "Peaky Blinders" is set primarily in the interwar period in Birmingham, and "Call the Midwife" chronicles post-war London but does not have the same number of series or films as "Downton Abbey."