According to this:
http://www.weddingguideuk.com/articl...prohibited.asp
'Marriage of Cousins:
Despite the long list of degrees of forbidden relationship, you can marry a cousin (courtesy of Henry VIII who changed the law to marry his cousin!). However, it would be sensible for you both to consult your GP to ensure that there are no factors in your family's health records that would make your decision to have children inadvisable on medical grounds.'