What was the name of the cbbc sci fi show about sone kids who use a metal suit

[Luke]

to fight crime? It aired on cbbc around 2000-2004.
There was an underground base in it, which had a talking head on a computer screen.
They also drove round in a van.
It had a bad guy, who had a red metal suit that was much faster, and I think it had a crab on it.
It was something to do with Silver, I think.
Thanks