Marcia Brent, Marchioness of Caterham is a recurrent character who features in both The Secret of Chimneys and The Seven Dials Mystery. She is the sister-in-law of Lord Caterham and the widow of his brother Henry, the 8th Marquis of Caterham who was formerly the Secretary of State for Foreign Affairs.
The Secret of Chimneys[]
In the Secret of Chimneys, Marcia is mentioned but does not appear in person. Here, George Lomax is planning a meeting at Chimneys and he suggests to Lord Caterham that it might be useful to have a tactful woman acting as hostess. Such a person could help achieve a diplomatic breakthrough. Lomax praises Marcia and the valuable help she gave her husband in that role. "Marcia was magnificent, unique, a perfect political hostess." However Lord Caterham is not keen on "his redoubtable sister-in-law" acting as a hostess beside him. On the other hand, he also considers his daughter "Bundle" to be useless in this role. They finally settle on Virginia Revel.
The Seven Dials Mystery[]
In The Seven Dials Mystery, she is highly impressed when her niece "Bundle" approaches her expressing an interest in learning about politics. She gets her secretary to give Bundle some reading material. She also helps wrangle an invitation for Bundle at the house party organised by George Lomax at Wyvern Abbey. Bundle is investigating a mysterious organisation called The Seven Dials. George Lomax had received a threatening letter about the house party from The Seven Dials so Bundle decides that she must be there.
Marcia Brent is not featured in the 1981 LWT adaptation of The Seven Dials Mystery.