Fuchcias - to cut back or not to cut back?

Hi, I have four or five Fuschcias in the green house, some of which are already sprouting new little leaves.  My question is do I need to cut off the old growth from last year, especially for those who are not showing any new signs of life yet?  Or should I leave them to keep happily growing?  Didn't know if I trimmed them up whether it will promote better growth for this season.

Many thanks for any help given.