Your decision to abort is made prior to V1, no matter how close to V1 this is.
If you have not made a decision before V1 and have not started the abort process, then you continue. If you don't then there is a very high risk of ending up in the dirt amongst the approach lights. (not pretty)
Anyway that is the theory I've been taught.......fortunately I've only had to use it in the sim!
