Can any one help me!

my escort cosworth has stopped working properly.

It will run for a short period of time then it will die and the ignition lights will come on and it wont start again, all i hear is a clicking from one of the relays behind the fuse box. after leaving for a while it will then start up. i cannot go anywhere in the car cos i'm in fear of it breaking down. any answers or any tests i can do.
any help appriciated