I am currently doing my PhD in Cosmology in Germany. I would like to apply for a postdoc position in UK. Targeted destinations would be Cambridge, Oxford and Imperial College. Do I have realistic possibilities of finding a position there, even though I have not studied for my PhD in the UK? I have the impression that in UK they tend to hire people coming from the UK.
Well I am studying for a PhD at Cambridge and most of the post-docs that I have met are not from the UK. I personally know at least 3 post-docs from Germany and a large proportion (24%) of the graduate students are from Europe (39% are non-UK/Europe). So from my experience Cambridge doesn't seem to preferentially hire UK post-docs.
The widespread rumour about Germany is that academic community in this country can be quite protective and unwelcoming to people from outside, especially when it comes to professorial-level posts. I dare to guess that your concerns about postdoc positions in the UK are in some way a projection of what you learned about academia in Germany. I do not think that in the UK there is a tendency to hire primarily people from the UK.
However, you perhaps should be wary of the following.
- The universities you target are extremely competitive
- The research funding budgets in the UK are typically less deep and more difficult to get compared to Germany. Usually Profs can hire not that many postdocs and PhD students, so the competition rises
- Postdocs are usually involved in teaching as well (some 1h tutorial class per week), and a good command of English can be something that people expect a successful candidate to have (even if it is not stated explicitly as a person specification criteria)