Depends what you mean by 'ok'
and it depends on the following:
1) What you are to use the loan for - (as an example if it is a car, a lender can 'secure' their loan by way of Hire Purchase etc - this makes it more likely for the loan to be granted.)
2) How much the loan is for
3) Why you have a low rating - is it because you have not paid your bills, or is it because a few years ago you had some problems but everything is paid off. - if all your accounts are up to date and any defaults / ccjs settled, then more lenders will consider you
On the other hand, if you mean by 'ok' that you want a loan and never pay off your existing credit, then as loosehead says, you will still be able to get a loan but not by a high street name, and you won't like it if you are late paying!