Here's the latest list of Individual Savings Accounts with the highest interest rates, instant access and fixed term, fixed rate ISAs: Instant Access ISA, best interest rate, Nationwide Online ISA. 1 year fixed ISA, best interest rate is Leeds BS, 1 Year Fixed Rate ISA (Issue 29). 2 year ISA, highest interest rate is offered by Halifax for a 2 year fixed ISA. 3 year ISA, best interest rate is from Aldermore Bank offering fixed rate of 3.8% ...