The Guest, BBC One review - be careful what you wish for

Why isn’t Eve Myles a superstar? Though well known for her appearances in the likes of Torchwood, Broadchurch and the brilliant Keeping Faith, you’d imagine that by now she’d have been snapped up for some mega-budget extravaganza on Amazon or Apple TV or be romping around with Tom Cruise.

But she obviously likes to keep close to her Welsh roots, as she does in The Guest, and it helps her deliver a power and authenticity that might be lost in the jungle of corporate streamer-land. She plays Fran Sharp, a wealthy businesswoman who lives in a splendid house in the country near Cardiff with her husband Simon (Julian Lewis Jones). Although Simon isn’t at home too often, since he’s frequently preoccupied with unspecified activities which underpin the couple’s exorbitantly lush lifestyle. Their business is called Maybury, a kind of Heal’s and Jo Malone hybrid aimed squarely at customers who have no need to check their bank balances before splashing out.But despite her sleek blouse-and-trouser outfits and ravishing hair extensions, Fran hasn’t forgotten where she came from, and we learn in due course that her background was anything but easy and affluent. When she comes across Ria Powell (Gabrielle Creevy) being roughly handled by an in-store security man for trying to steal a loaf, she feels an instinctive pang of sympathy... or is that all it is? Ria is trying to scrape a living as a house-cleaner, and has just been sacked by one client for refusing to take a cut in pay to £9.50 an hour. Fran promptly employs her for a princely 20 quid an hour (pictured above, Creevy and Emun Elliott).

Writer Matthew Berry uses the apparent social divide between Fran and Ria to drive the drama, as Ria gradually falls under the spell of the glamorous and wealthy older woman who seems to be promising her a new life beyond anything she’s ever experienced, with apparently limitless horizons. Soon she’s not a mere cleaner but Fran’s personal assistant, and is given her own live-in apartment. It’s worlds away from her previous existence in a council flat with her dorkish boyfriend Lee (Sion Daniel Young), who keeps saying he’s looking for a job while being glued to his PlayStation 24/7. But Fran assures Ria that the sky’s the limit, if she can only throw off her hereditary low expectations. Ria shouldn’t be satisfied with mere crumbs, she insists – “take the whole fucking loaf!”

But you know what they say about things that look too good to be true, and they’re not wrong. The Guest unveils its secrets and lies methodically, steadily reeling the viewer in as the story develops into various unexpected dimensions. Ria becomes obsessed with the unknown fate of another girl, Anna, who also lived at the Sharps’ home and apparently made regular trips to Dubai. And what is she to make of the elderly Derek (Clive Russell), the father of Fran’s suspiciously close friend Richard (Emun Elliott), who dramatically warns her to “get out of here while you can”?

The show is splendidly served by its strong ensemble cast, Myles leading the way with an assured aura of command. It’s also given extra flavour by the deployment of some striking Welsh landmarks, including Cardiff’s Principality Stadium and the astounding scenery of Rhossili Bay. Dive in, the water’s lovely.

• The Guest continues on BBC One on September 7 & 8. All episodes available on BBC iPlayer
• More TV reviews on theartsdesk