It makes no difference, when your spouse died, the value of your allowances for inheritance tax, automatically transferred provided you were married and your spouse left everything to you. So whether your spouse died 10 years ago, or whether your spouse died several months ago, makes no difference.

You would still get their residential nil rate band provided they owned a share in a main residence in the UK, and you would get the normal nil rate band, no matter what, provided you were liable to inheritance tax in the UK.

The allowances transferred irrelevant of the date of death is the main point.

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