Morgana Robinson's The Agency is funny. Her impersonations are often uncanny, particularly those of Natalie Cassidy and The Bake-Off's Mel and Sue. And her show isn't a stand-up, Rory Bremner-style impressionism where she stands at a mic. Instead, she weaves it into a loose story where the celebrities are represented by a talent agency, Mann Management, and she presents it as a documentary about the company.

But even though I laughed, particularly at the cruel Natalie Cassidy segments, I was left feeling slightly empty afterwards because isn't it a bit of a waste to use that huge talent for impressionism on such a flimsy figure as "Sonia from EastEnders". Of course, that was part of the joke: she's only little old Sonia yet thinks she's a great star, but I wanted to yell at Robinson to turn her firepower on bigger, more deserving, targets.

It must be harder these days to do political impersonations as politicians are so bland and "on-message", and mavericks and colourful characters rarely slip through the antiseptic net. You can't do an impression of a bland person who's been planed smooth by the party PR machine yet, in a world where politics has thrown up Trump, Brexit and the tortuous splitting of the Labour Party, aren't things changing? And where are the comedians and satirists ready to react to that change?

Morgana Robinson's The Agency, a new sketch/impressionist show, uses a narrative format to showcase her talents. It's set in Mann Management, a talent agency run by Cavan Clerkin's Vincent, who has let documentary cameras in; Robinson plays his clients.

Some impressions work better than others - Robinson's Natalie Cassidy (Sonia from EastEnders), Cheryl Cole and Fearne Cotton are uncannily good - while others (Danny Dyer, Gregg Wallace) are surprisingly off the mark. Where last night's opener (of seven) did score, however, was in the fantastical writing (five writers are credited) - imagining an endlessly disappointing suburban existence for the always optimistic Cassidy, or the rather creepy menage imagined in the scenes chez Mel and Sue, where Mel's husband has to grit his teeth at their relentless punning.

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The variety is so broad that it's impossible to watch her, in or out of character, without thinking: 'I've seen her in something else...'

No one is safe from Morgana the mimic

In Morgana Robinson's The Agency, the comic shares her surreal impressions of famous folk. It's all about finding that 'hidden something' in her subjects, she explains.

An actor working in impressions builds a house on generally unfunny sand and, mindful of that, Morgana Robinson has tried to give her show a bit of additional conceptual weight. Her idea is a mockumentary following clients at a fictional talent agency which represents all the celebs she impersonates, such as Mel and Sue and Joanna Lumley. Maybe too much prominence is given to Natalie Cassidy, but the Gregg Wallace stuff is pretty decent.

Morgana Robinson's The Agency preview

It seems simplistic to call The Agency an impressions show. For Morgana Robinson is less a straightforward mimic than she is a caricaturist, creating exaggerated characters only loosely based on celebrities' real personalities. And this is a fine format for her talents.

Preview: Morgana Robinson's The Agency, BBC2

Morgana Robinson has been on the cusp of fame for a few years now. She had her own character-comedy show The Morgana Show six years ago and since then has been cropping up in shows such as House of Fools, The Windsors and Charlie Brooker's Wipe programmes where she did a mean Russell Brand.