George Osborne announced in the Autumn Statement that the owner of an ISA can now pass on the tax allowance to their spouse or civil partner. This new legislation has been enforced as of 3rd December 2014, but allowances will only take effect as of 6th April 2015.
Previously when a person died, their spouse was unable to inherit the tax-free benefits of an ISA. This even applied to accounts in which each spouse made contributions. This had reportedly affected around 150,000 who missed out on any potential tax gains.