The spouse or civil partner of ISA holders who have died have the ability to inherit their ISA allowance.
The Inheritance ISA or 'Additional Permitted Subscription' (APS) rules allow you to use your partner's ISA allowance for up to three years from the date of their death or 180 days after the completion of the administration of the estate, if longer.
The spouse or civil partner can then inherit their ISA allowance which will be equal to the amount held by the spouse or civil partner in their ISAs. For example, if they inherited an ISA allowance of £80,000, then during this time, an additional £80,000 could be held in your ISA. This is on top of your own annual ISA allowance of £20,000 that comes into effect from 6 April 2017.