In the scene where the news of the Russian invasion reaches the House of Commons, the members pass the news down the rows, one by one. However, several of the members start sharing the news before they could possibly have heard it from anyone next to them. The scene looks good, but doesn't hold up to scrutiny.
The two Strauß waltzes played at Count D'Orsay's party and attended by a young Disraeli were both written after Disraeli's death in 1881.
Prior to the party where Mary goes to meet Benjamin, a close-up shows the party invitation, dated June 1837. Following the party, Benjamin gives a coach driver a gold sovereign coin, and a close-up shows it is dated 1839.