Julian Fellowes’s long-awaited new series is a gritty take on life in a council block in Luton. Just kidding! The Gilded Age (Sky Atlantic) is, obviously, a lavish period drama featuring beautiful frocks and heavy curtains and characters who say Dynasty-esque lines such as: “I may be a bastard, Mr Thorburn, but you are a fool, and of the two I think I know which I prefer. Good day to you, sir.”

It is set in 1880s New York, and chronicles the clash between old and new money. Made primarily for a US audience on HBO, its producers – who include Downton Abbey’s Gareth Neame – are at pains to remind viewers that this is from the Downton stable. The opening scenes take us below stairs to a flustered cook and a butler very similar to Downton’s Mr Carson.

Upstairs, the imperious Agnes van Rhijn (Christine Baranski) lives with her kindly sister, Ada (Cynthia Nixon). Agnes is appalled at the newcomers moving into the grand mansion across the street: robber baron George Russell and his hyper-ambitious wife, Bertha (Morgan Spector and Carrie Coon). Meanwhile, Agnes and Ada’s penniless Pennsylvanian niece, Marian, comes to live with them after her father dies.

Marian is played by Louisa Jacobson, who may have picked up some acting tips from her mother, Meryl Streep, and here makes a very strong television debut. Like us, Marian is a newcomer to this world, navigating its social mores. Agnes schools her on the class divide: “We only receive the ‘old’ people in this house. Not the new. Never the new. The old have been in charge since before the Revolution. They ruled justly until the new people invaded.”

It is handy to keep reminding oneself of this, because to 21st-century eyes there is little material difference between the new money Russells and everyone else. They all have enormous houses and expensive attire. But there is a strict social code here, with which Fellowes is obsessed. I lost count of the times people namechecked “Mrs Astor” in breathless tones.