Factual error: When Victoria and Albert visited Blair Atholl in 1844 (actually two years before the events depicted in the previous episode, which occurred in 1846), the Duke of Atholl was mad and locked away in a London townhouse, as he had been for 46 years. The man who hosted them and is depicted by the 70-year-old Denis Lawson was actually his nephew and heir, Lord Glenlyon, who was then only 30 and succeeded his uncle as duke in 1846.
Factual error: Drummond's assassin is said to have been a farmer who was angry about the repeal of the Corn laws. He was actually Daniel M'Naghten, a woodturner who was found not guilt by reason of insanity and was under the delusion he was being persecuted by the Tory Party. Drummond did not take a bullet for Peel. Peel was not with him at the time. M'Naghten mistook him for Peel as he left Peel's house and shot him in the back.