Maggie Smith nominated for BAFTA. Why no one else?

Maggie Smith has been nominated for a BAFTA for supporting actress. She's been nominated four times for television work in the past, but has never won. Maggie is the only Downton Abbey nomination.

There's no doubt that Maggie is deserving of the nomination. The Dowager Countess has become a fan favorite. I only wonder why no one else was nominated. Michelle Dockery and Joanne Froggatt absolutely deserve it, as do many others in the large ensemble cast.