42 was written in response to the popular TV series 24, in which the action takes place in real time over 24 hours divided into 24 one hour episodes. Chris Chibnall took this concept and applied it to an episode of Doctor Who, having the entire episode taking place over 42 minutes in real time.

To me, this really benefits the episode. It makes it feel 'real', as though we're watching events take place as they actually unfold. It's a clever concept and one that I applaud Chris Chibnall taking from 24. Kudos to him also for making a Hitchhiker's Guide To The Galaxy reference by having it 42 minutes as opposed to 45 (although this episode isn't quite the answer to life, the universe and everything).

The story follows the Doctor and Martha arriving on the spaceship S.S. Pentallian after receiving a distress call and find that it is out of control hurtling towards the sun.The sun starts possessing the crew angry at them for illegally using it as fuel and the Doctor and Martha have 42 minutes to save them and the ship.

This is a fun and lively action-orientated episode of the show but it also has a few very creepy moments such as when the Doctor also finds himself possessed. It features one of the greatest moments you can have in Doctor Who that has been done a few times in the new series, where the Doctor himself is no longer in control and is scared of the situation. If the Doctor is scared, you know they are in deep trouble and Chris Chibnall plays this brilliantly.

It's not all good; it isn't the best episode by a long mile. It can feel a little generic and the scene at the end with Francine's call being monitored by a group of people working for Mr Saxon feels a little shoehorned in. It doesn't get the recognition it deserves though as a great episode of series 3. It is definitely among the strongest Chris Chibnall has written for the show.

One of the greatest soap actors Michelle Collins features too. Michelle Collins is known for playing Cindy in EastEnders (a show that I personally hate) and Stella in Coronation Street. Here, she plays Kath McDonnell and provides one of the best supporting character performances of the show. She is very believable and whilst not good enough to be recurring character status, provides a very strong portrayal of a character who is desperate in the circumstances of the ship's crashing.

David Tennant and Freema Ageyman are on top form, especially David Tennant who is unbelievably scary when he is possessed by the sun. I think this is one of David Tennant's finest performances as the Doctor; it's just chilling when he utters 'Burn With Me, Martha'. Those four words have a powerful effect on the audience in not only showing the lead character possessed but also in David Tennant's performance that there is still a bit of the Doctor there who's scared and doesn't quite know what to do. This is why David Tennnant is the best Doctor; he gave such a layered performance in the role.

Overall, 42 is a great episode told in real time with strong action scenes and some scary moments. Some may find it generic and the end scene is a bit forced to suit the Mr Saxon arc of series 3 but Michelle Collins is great as Kath McDonnell and David Tennant is terrifying as the possessed Doctor.