Is it possible to convert a suspension fork to rigid by drilling it? I have been given a Falcon MTB. I've sorted out all its troubles but the front suspension fork is worn.
When using the front brake the slack in the tubes make them judder. Is there anyway I can "solidify" the fork as I don't need suspension. Can I drill it back to front and put a bolt through or something like that?
DO NOT DRILL HOLES IN YOUR FORKS

That would weaken them substantially and run the risk of them breaking under stress (e.g., when you hit a pothole). A broken fork will probably put you in the emergency room, and potentially the morgue if you're unlucky with vehicles nearby.

Hopefully, other answers will address how to fix your forks; worst case is replacement, which isn't crazy-expensive for rigid forks.