Note the highlighted word: gifts. Your argument is basically that since gifts are included as a subset of inheritance, that this means that this is an inheritance tax instead of a gift tax. But that isn't so. It's still a tax on gifts. That one could also call it a tax on inheritance (by using a definition of inheritance which includes gifts) doesn't mean it's not still a gift tax. It is.
Is it also a house tax? And a medal tax? And a jewellery tax? And a car tax? And a designer dress tax?
It's an anti avoidance measure to make sure people don't give away or claim to have given away all their money just before death meaning no inheritance tax is due. A bit like how if your employer gives you a "gift" of your salary every month instead of a salary that is still taxable as employment income. Or are you going to claim income tax is a gift tax as well because it can apply to "gifts"?
There's nothing complicated about this. It's a tax on gifts. Therefore, it's a gift tax, by definition. You have done nothing to demonstrate that there is no tax on gifts (quite the reverse, in fact), and you have proposed no alternative definition of a gift tax (that is, a tax on gifts) wherein a tax on gifts is not a gift tax. How can you fail at comprehending something so simple?
There is nothing complicated, but you are wrong. What determines whether tax is payable is the death of the donor - its an inheritance tax.
Take two examples:
In the first a gift of £1m is paid and the donor survives for 10 years from the date of the gift. Nothing is taxable because it is not a gift tax.
In the second the same gift of £1m is made but the next day the donor dies. The full amount is taxable because it is an inheritance tax and the donor has died.
Same amount of gift, but the tax status determined by the death of the donor. Because it is an inheritance tax.
"Does the UK Have a Gift Tax?:
Currently the United Kingdom, including Scotland
does not impose a gift tax, which is a tax on monetary gifts you bestow on others. This does not mean, however, that every gift will be tax-free. Depending on when you make a gift, it could be liable for the inheritance tax. "
http://www.scottishwillservices.co.uk/deathduty.html
"As outlined there is currently
no gift tax in place in the UK however, there is a potential future liability for inheritance tax, when gifts are made, which would be payable on death."
http://www.accident999.name/tax.html
"At the present time, there is
no gift tax in the UK. "
http://www.contestedprobate.co.uk/inheritance.html
"This is probably because the UK has
no gift tax as such"
http://www.sykesanderson.com/Service_France/articles/french_gift_tax.asp
"In the UK there is currently
no gift tax in operation"
http://www.willsprobate.co.uk/tax_planning.html
You'd better tell all these people, working professionally in the field, that they are wrong because they all state there is no gift tax in the UK. Maybe they are all wrong or lying on their websites, or maybe you are wrong. Which seems more likely?
And of course your conclusion from the report that incorrectly claimed the UK had a gift tax was that pre and post death gifts were treated in fundamentally different ways. Which is not consistent with both being subject to EXACTLY THE SAME TAX.