Susan MacClare, also known as Lady Flintshire, was a character on the UK-US period drama, Downton Abbey. She was played by actress Phoebe Nicholls.
Rose's flint-hearted mother
Susan is the niece of Violet Crawley, the dowager countess of Grantham (Susan's mother is Violet's unknown sister) and the mother of Lady Rose MacClare. She was married to one Hugh MacClare, called "Shrimpie", who worked at the Foreign Office in London, and with him had three children ("Shrimpie" was so called because he was the smallest after his two sisters, Agatha and Louisa).
Besides Rose, the youngest, she had an older son named James, the Earl of Newtonmore; and another older, married daughter named Annabelle. It is clear that she favors her older daughter, Annabelle, over Rose.
We first meet Susan in the final episode of the third season at the MacClare family estate, called Duneagle in Scotland (It is the same episode where Mary gives birth to her son, George, and her husband Matthew is killed in a car crash). While she is cordial to the family, she has a lot of problems, some of them of her own making.
It is clear to everyone that she and Rose have a relationship that could be best described as contentious. As it turns out, she also has a contentious relationship with her husband. There are rumors circulating around that they are planning to divorce.
Susan thinks she can dictate to anyone what she wants and they are to jump to for her. Shrimpie, at one time, yells at Susan to quit making trouble for Rose where there is none.
She gains the trust of lady's maid, Sarah O'Brien, and, after firing her former lady's maid, Wilkins, would eventually convince her to join her staff, when they move to India. This perfidy would aggravate her cousin in-law, Cora Crawley, to no end. She would end up going through another lady's maid, before she would be pleased with Phyllis Baxter.
We don't see Susan again until the next to last episode of the fifth season. She is at her troublemaking worst, when she tries to sink her own daughter's wedding. It is clear that it is done out of sheer spite, due to Susan's clear hatred of Rose and a desire to not want her to be happy.
She pays a tart to seduce Rose's fiancé, Atticus Aldridge, and hired a photographer to take pictures. When the plot was revealed, Shrimpie orders her to stop her disgusting behavior, but it is clear that she doesn't and will not. Her intent is to make Rose unhappy, and nothing will stop her.
At the wedding itself, she reveals that she and Shrimpie are divorcing, to the anger of Daniel Aldridge, Lord Sinderby, who is very much against divorce, due to his Jewish faith. However, his more understanding wife, Rachel, Lady Sinderby, tells her that as they were forewarned ahead of time, they are forearmed and are ready to weather that crisis.
Rachel also angrily threatens her husband to not stop their son's marriage or else she would leave him and really cause a scandal. It is clear that Rachel wants her son happy, and is not afraid to put her husband in his place when he gets out of hand, similar to how Shrimpie was to Susan.
Susan, totally vanquished, tries to justify what she did to Rose, claiming it was done out of love. Rose, however, tells her selfish mother that they have very different meanings of the word, and she turns her back on her. Rose then finally feels free of her hateful mother.
After that, Susan is never spoken of or heard from again. By the last season, Shrimpie is presumed to have finally divorced Susan, as it was only he who was in attendance at Lady Edith Pelham's wedding and he was giving the speeches.