2002 Vauxhall Corsa no compression on any cylinder

Check the camshaft is ok and turning.

I'd go a little further than Whighthame,
you ought to have at leas some compression on one at least
unless the timing chain has jumped teeth.

unusual for no compression on all cylinders unless valves are bent due to a jumped timing chain first thing is get valve timing checked if ok have a cylinder leakage test done

As above.Timing chain or camshaft snapped are very common and what I was inferring .