From the Guardian, 18 May:

"The Queen will not have to pay inheritance tax on her mother's estate, valued at between £50m and £70m, thanks to a deal reached with John Major's government nine years ago when she agreed to pay tax for the first time. The agreement meant that the sovereign's bequests are not liable to taxation. The palace maintains the arrangement is necessary to preserve the sovereign's financial independence and to compensate her for not being able to earn her own living."

Looks like the old girl REALLY has something to celebrate, wouldn't you say?

As ever, getting it over on us.