The other V is an insult.

Legend has it that the French used to cut off the first two fingers on the right hand of captured English archers (the English longbow was a decisive weapon used on the battlefield during the 100 Years War, amongst others, proving particularly deadly to the French mounted kernigguts), so the English - being the way we are - waved our fingers at the French in a V-sign.

Known as "flicking the Vs".