Hacksaw. Coke-can. What more do you want?
There is a story behind why Jon had a hacksaw. In brief, he wanted to
cut through the D-Lock on his bike as he'd lost the key for it. Matt
contested that he wouldn't be able to do it, and that he should try
sawing through a coke can, then upscale the effort required. It took
him a surprising amount of time, but he managed it in the end. He did
not, however, manage to cut the D-Lock, which merely served to sever
all the teeth from the saw.