Yeah if it's a B&Q or Maplin special the fittings have probably rusted away due to not being galvanized and I would bet that your coax has probably oxidised badly at the terminals.
Get a new antenna up as Heero says (decent one, not the above type or it will fall apart again) and I would recommend painting some liquid tape over the feed-point terminals and exposed braid/conductor after connecting the coax.
Liquid Tape