promotion

when a pawn reaches the end of the board, must it be promoted?

(before people come back to me and say why wouldnt you promote it i'm not disputing that, just wondered if there are any rules to say you must promote it)

thanks

Yes, it must be promoted.

Yes the pawn must immediately be replaced by a queen, rook, bishop or knight of the same colour. However that wasn't always the case:
http://en.wikipedia.org/wiki/Promotion_(chess)#Old_promotion_rule