You've just heard of the beginning of the first verse of this British popular verse.
Below is its full version :
The fifth of November
Gunpowder, treason and plot !
We see no reason why
Should ever be forgot !
Guy Fawkes, Guy Fawkes, 'twas his intent
to blow up the King and Parli'ment.
Three-score barrels of powder below
To prove old England's overthrow ;
By God's providence [or mercy] he was catch'd
With a dark lantern and burning match.
Hulloa boys, hulloa boys, let the bells ring.
Hulloa boys, hulloa boys, God save the King !"
Here it is, in an excerpt from the film :
It presents the beginning of the popular verse too : but now it's the man with a mask -"V"- who recites the verse and not Evey any more !