Doctor Thorne, ITV

As the camera lingered lovingly over landscaped gardens and ravishing English countryside with a stately home parked squarely in the back of the frame, one could hardly avoid slipping into a Downtonesque reverie. Even more so when the assembled posh personages arrayed prettily on the greensward began to discuss marriage and inheritance, triggering echoes of the fabled Downton "entail".

Clearly, screenwriter Julian Fellowes is not minded to relinquish his grip on ITV's plum 9pm Sunday slot, and his motto may be "if it ain't broke, don't fix it any more than you have to". If he couldn't bring us Downton II – On One's Uppers, he would make do with a Julianisation of a chunk of Anthony Trollope's The Chronicles of Barsetshire.

For a time, it was looking perilously like Bah! setshire as we were introduced to a roll-call of bossy matriarchs, nice sisters, bitchy sisters and unsuitable suitors, as though Fellowes had hastily bolted together a sampler of all the televised novels you've ever seen, from War and Peace to Pride and Prejudice and The Forsyte Saga. However, the author's tone of twinkling acidity gradually began to assert itself, and while there are unlikely to be any violent leaps into fourth-wall-shattering avant-gardism, it's quite agreeable to sit back and watch a rather fine cast do their stuff. You can bring your own bottle of port.

You won't go far wrong with Rebecca Front as Lady Arabella Gresham, doing her aircraft carrier-ly best to steer the Gresham dynasty away from the treacherous reefs of debt onto which her husband Frank (Richard McCabe) has recklessly steered it. To this end, her dear but naive son Frank Junior (Harry Richardson, sporting racy One Direction hair) must be headed off from making further passes at the lovely but penniless Mary Thorne (Stefanie Martini, pictured above with Richardson).

Arabella's beady-eyed sister, the Countess de Courcy (played like a one-woman SWAT team by Phoebe Nicholls, pictured below with Rebecca Front), had lined up a vastly more desirable match, from a book-keeping point of view at least. This was the wealthy American, Miss Dunstable (Alison Brie), though in one of the more enjoyable exchanges, Miss D showed that she cherished no illusions about the squadrons of suitors constantly manoeuvring around her. "Come Mr Gresham," she hooted to Frank, "we both know it is not my beauty but my dollars that render me lovely in their sight."

What we needed now was a robust bit of rough, so up stepped Ian McShane. He plays Sir Roger Scatcherd, once a humble stonemason, but now the brandy-sodden owner of the big house on Boxall Hill. He also stands a good chance of acquiring the Greshams' Greshamsbury Park estate, since his loans to them amount to three-quarters of its value.

But Sir Roger has a chequered past. He served 10 years for the manslaughter of the brother of the titular Doctor Thorne (Tom Hollander), though despite this he and Thorne have become friends as well as doctor and patient. With Hollander's droll rationality balancing McShane's bellowing mood swings, this is set to become one of the most entertaining relationships in the piece. Also a crucial one, since while Mary Thorne is the doctor's niece, it seems she also has a secret lineage that may prove of immense value...