Just to clear this up for anyone who is wondering:
You do not need Further Maths to get in to the Economics Tripos. However, it does help a lot. And the level of Maths in the tripos itself is high enough that you will wish you'd taken it.
I'm currently studying Economics at Cambridge, and even having done FM some of the Maths is still quite challenging. Some other economists in my college who haven't taken it, however, find it miles harder. (Proof you don't need it, but that it helps) Also, may I suggest you focus on the stats papers.. It will make your life miles easier. Good Luck!