I like Anne-Marie Duff - heavens, for once in my life I'd booked weeks in advance - but her new play Oil at the Almeida is a bit of a mess.

It opens in 1889 on a grim Cornish farmstead that seems to have been modelled on Van Gogh's Potato Eaters, with a dash of Cold Comfort Farm thrown in for good measure. Not that anybody will be able to see anything nasty in the woodshed because these Starkadders are still dysfunctioning by candlelight -  when, as you can see, even the miserable Potato Eaters (1885) have embraced paraffin lamps that I'm pretty sure have been around for decades. Heigh ho ... well, you can see why pregnant Anne-Marie wants out when the Esso Blue man calls and turns on the lights. Before we know it, she's time-travelling through decades of squandered fossil fuel and global politics - until finally she and her daughter end up in a dystopian near-future where the lights have been switched off, they can't afford the leccy, and the Esso Blue man calls again but this time he's selling something nuclear. Oh, it's all very well-meaning - and there's a good dollop of Guardian feminism along the way - but sitting there for 2hours 40 mins felt like being hectored by an intense adolescent eco-warrior. Seemed like quite a few in the seats near me voted with their feet after the interval - and they didn't miss much, because with every time-change the play gets progressively less engaging. But I still like Anne-Marie Duff so I'll be generous and give it 6/10. When you've only paid £10 for a seat - and the Almeida's restricted view seats aren't all that restricted - well, that's less than a cinema ticket, so who's complaining?