Does anyone know where I can get a hand held microphone which can secretly conceal a small load such as a bank note, billet etc. much appreciated!

I would think a TT would be easier to use than searching for a microphone with a compartment.

Or, you could put a wide elastic around the microphone and conceal the bill or billet under that.

Thanks, what do you mean by TT?

Not sure if your familiar with the lottery prediction routine. It is mainly for this, where I would make this switch using a clear full view switch box or maybe even jay Sankeys paper clipped!

Just toying round with ideas, to see what works best for my stand up show

There are many different microphone switches you may want to check out. Cassidy is one that comes to mind.

There are a few models of wireless microphone that have a battery compartment. I'm not sure if any will accommodate both the batteries and the billet.