I haven't seen the poster for Man Up yet but, judging by its determination to ignore what's working and be the blandest, clichéd-ridden porridge you'll see this year, I'd imagine it's tagline reads something like 'She's on the best first date of her life... but it's not hers!' or some terrible nonsense like that. This is a shame because if Man Up was left alone, if they didn't try and slip in Rom-Com Moments 1-58 (inclusive), if they just let Lake Bell and Simon Pegg bounce off each other, then this would have worked.

Thirty-something cynic Lake Bell usually stays well away from romance, squirrelling away in a hotel room watching Silence of the Lambs instead of getting busy at the themed cocktail party downstairs. But when jolly Simon Pegg mistakes her for his blind date, she takes sis Sharon Horgan's advice and goes along with it, pretending to be the date. They hit it off but as the night progresses secrets on both sides come to light...

Man Up is all over the place. It's bad, then good, then bad, then good, then good for a while. Then it's really bad, then worse, then terrible. Then kind of good again. When it's bad it's because director Ben Palmer (The Inbetweeners Movie) and writer first time writer Tess Morris are probably listening to execs who demand that X and Y are in the movie because X and Y are in movies like this. The X and Ys here are:

- Slagging someone without realising that that someone is standing right in front of them.

- Slagging someone without realising that that someone is standing right behind them.

- Slagging someone without realising that that someone is dead.

These three things happen in one early scene. How very British. How very Richard Curtis. How very 1994. Then we have the naff dancing scene. The speech scene. The run-for-the-airport (or, here, the down the street) scene. It's rom-com 101. It gets worse: When the secret comes out, there are two believable developments:

1. They laugh it off and continue on their great date.

2. Awkwardly say goodbye.

What wouldn't happen is that both parties engage in a race across London for a misplaced satchel. This happens. This actually happens. An example of when people who can't write have an influence on what's written. Damn execs (shakes fist).

But then we have the pockets of good, and they're down to Lake Bell and Simon Pegg's nervous energy. When they're allowed at it, the dialogue is zippy and the movie bustles along. It's fun hanging out with these two. They're so engaging, in fact, you tend to forget how bad the movie can get. Such a shame.