I’m pretty sure I’m correct but I can’t find anything unambiguos online to back me up.
I have friends/neighbours who are an unmarried couple, they jointly own a house worth around £450k, they are early 50’s with no mortgage, both NHS with DB pensions, not sure about savings, no wills and the Woman has one adult DD.
They do not believe me when I try to explain that IHT will be due on anything above £325k if one of them dies, both absolutely believe that only half the house value will be counted - they are definitely not tenants in common ( I’ve even checked the LR to be certain).
Nothing I’ve said about jointly owned property being owned as a ‘whole’ has got through to them.
Legal websites I’ve looked at state IHT will be payable but in very vague terms, nothing I’ve found mentions the whole value of the property as concrete evidence.