If you have savings with Northern Rock or any other institution,I think the first �35,000 is safe should they become insolvent.
If you have a mortgage then I don't think much would change - an interest rate increase at worst.
But if you're a share holder,as I understand it you will potentially lose your money.
I heard somewhere recently that the share price about a year ago was about �12 per share and it is now only about �1. So if you'd bought shares a year ago you would have lost most of your money.
Remember,share prices go down as well as up.