I know that in continental Europe a blazer and a pair of flannel trousers are seen as elegant clothing for a formal dinner which doesn't require Black Tie or anything higher. The same would probably be true in the United States. However, when is it acceptable to wear a gold button marine single breasted blazer with tie, shirt, flannel trousers and handkerchief in the UK? I don't ever recall seing any member of the Royal family wearing a Blazer nor did i ever see any of my British friends wearing a Blazer except one, when we were sailing in Bexhill. For instance would it be acceptable to go to an event such as an accolade ceremony given by the Queen (occasion to which men seem to dress in suits), to come dressed in your favorite Blazer, flannel trousers, your best shirt and tie? I think that to some extent a well cut blazer with the right trousers can be far more elegant than a suit.