Hi

 I really need advice.. I am making a surprise birthday cake for my sister in law for the weekend. I am making a chocolate biscuit cake.. as I feel this would be the easiest to transport as I will be travelling by BUS!! I am only making a  one tier cake but it will be iced in fondant.

There will be 15 people there so I presume a 9" will be plenty.?

How can I transport this successfully without the surprise being ruined as she is collecting me...Is there a bag that fits boxes or would a hat box work!?

Help please ..thanks in advance. 

AIn a box should be fine. Stick the cake to the board with butter icing or royal and just be really carefull. I have travelled fine this way on two buses . Just thank The Lord it isn't two teir!

A 10" cake box will fit into most reusable shopping bags, the type sold at many grocery stores.  Some of those bags have a rigid plastic piece in the bottom, others are soft and you can *carefully* lower a 10" box right in.  Plop some personal belongings on top and no one will be the wiser...