Gilera runner vx 125 electric start wont work

I noticed yesterday it was taking a bit to get the engine started and now this morning it wont start at all, it makes a clicking sound and the electrics go dead but when i release the back break the electrics start up. any ideas?

 

Dead battery? Don't forget you'll be actuating the rear brake light and when you release it what voltage you have will go back to the ignition.
If the battery is 3/4 yrs old just get a new one.