Which scandal did Lavinia Swire help Sir Richard Carlisle's newspaper expose?

Lavinia Swire helped Sir Richard Carlisle's newspaper expose the Marconi scandal. The scandal involved allegations that senior British politicians had profited from advance knowledge of a lucrative government contract involving the Marconi Company.

In Downton Abbey's second series, Lavinia possesses evidence connected with the affair and shares it with Carlisle, the powerful newspaper proprietor courting Lady Mary. The material gives his paper a potentially explosive story and shows how Lavinia's family connections reach into high-level political and financial circles.

The real Marconi scandal broke in Britain in 1912. Ministers and other political figures were accused of buying shares in the American Marconi company after learning about the government's planned Imperial Wireless Chain contract. A later parliamentary investigation found that ministers had bought shares, though the committee disagreed about the seriousness of their conduct.

The other options belong to different historical contexts: the Dreyfus affair began in France, the Profumo affair unfolded in Britain in the 1960s, and Teapot Dome concerned the United States in the 1920s.