Being awarded a fellowship is an important step towards a developing your own research program and gaining permanant research position. Here is a list of some of the releveant larger fellowships in the UK.
Daphne Jackson Fellowships
Dorothy Hodgkin Fellowships
EPSRC postdoctoral fellowships
European Research Council
Marie Curie European and Global Fellowships
Newton International Fellowships
Royal Society University Research Fellowships
STFC Ernest Rutherford Fellowship
You will need to apply in conjunction with a research institution, so check out this list of spintronics research groups in the UK.