I made this cake last year for the Diamond Jubilee and as an assessment piece for the college course that I was attending.  The crown was made from sugar paste on a small round plaque as I wanted to put jewels on it and anything that is not edible should be made to be easily removable from the cake for cutting.  The jewels I got from Hobbycraft. I made the flowers from sugar paste these being roses and carnations.

The cake is an 8″  sponge cake covered with white sugar paste   The frills are red white and blue and I used a frill cutter to make these. The frills were a bit if  a fiddle at first and I had to make a template from grease proof paper to ensure that they were put onto the cake evenly.  I measured the circumference of the cake and cut out a piece of paper to that length and width of the cake.  I then folded it into quarters and cut out a half circle.  This gave the template to space the frills evenly.  I placed the template on the side of the cake and used a scribe to mark out the placement of the frills.  After cutting out the frills I used a toothpick to frill up the edges.  It took some goes to get it right but worked out in the end.