In order to do some voluntary work!!
I filled in all the forms and took in my passport and driving license to show them and told them then that I chose to keep my name when I got married. It was a part of my identity that I didn't want to change and as it turned out was the right decision as the marriage didn't last. We are not officially divorced so I am technically married. I am quite cross about being asked to explain this again, I really don't see what business it is of theirs.
I didn't realise I was being particularly radical by doing this, I guess I am more of a feminist than I knew!