I am just going into my fourth year of a 4 year MSci course and have got my results from my third year. It's not as good as I had hoped and my average is a 2.1. I know that Cosmology is very difficult to get into and PhD's are over subscribed. I was also hoping to work at one of the Internationally recognised institutes like Sussex, Cambridge, Oxford, Imperial or UCL. Other than my grades I think I am a strong candidate as can talk fairly fluidly on the subject, have a long list of extra-curricular activities/projects and have good references. So my question is, when should I apply for my PhD, should I apply this year or wait until after my 4th year when I hope to pick my grade up to a 1st?