The annual ISA allowance may vary each tax year. The ISA allowance for 2017-18 tax year is £20,000. When you are funding your Ablrate IFISA we have an automated check on what allowance you are allowed to invest so that you don’t over-fund accidentally.
You may consult the government website for the current ISA allowance.
PLEASE REMEMBER, REGARDLESS OF THE TAX BENEFITS, CAPITAL IS AT RISK
Whether investments are held within an IFISA or in a general account, they are not covered by the FSCS; the government-backed deposit insurance scheme that protects bank deposits including Cash ISAs.