You have what is called a controlling interest but that doesn't mean you can do absolutely everything you like. What does the Articles of Association say, if anything?
This website may help you.
http://www.shareholde...k/rights_frameset.htm
Further down there is a table on rights of shareholders - look at the >50% but <75% tab. It seems that you can remove a director at a general meeting of shareholders provided it is done as an 'Ordinary Resolution with Special Notice'.
I take it the 40% shareholder is the other director? Messy.