You might have savings elsewhere or in a cash ISA that is earning so little interest (you'll be lucky to be getting 0.2-0.4 percent interest in an instant access savings account at the moment), so you might consider moving cash that's earning almost nothing to an alternative such as a S&S ISA. Obviously there's more risk, but also more chance of a reasonable return.
If you do transfer in from one ISA to another, do make sure you use your new provider's procedure for ensuring a transfer with no loss of the tax-free status and no use of the year's tax-free allowance. You don't want to close down a cash ISA and put the money into a S&S ISA, you want to make your new provider do a transfer from your old provider into your new S&S ISA.
