If Her Majesty by Order in Council declares—
the arrangements shall, notwithstanding anything in this Act, have effect so far as they provide for relief from inheritance tax, or for determining the place where any property is to be treated as situated for the purposes of the tax.
For the purposes of this section, arrangements made with a view to affording relief from double taxation include any arrangements which modify the effect of arrangements so made.
Arrangements to which effect is given under this section may include provision conferring (with or without other functions) functions relating to the determination of matters arising under the arrangements on a public authority in the United Kingdom or in a territory outside the United Kingdom.
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Any arrangements to which effect is given under this section may include provision for relief in cases occurring before the making of the arrangements and provisions as to property which is not itself subject to double taxation.
Any Order in Council under this section which revokes an earlier Order may contain such transitional provisions as appear to Her Majesty to be necessary or expedient.
An Order under this section shall not be submitted to Her Majesty in Council unless a draft of it has been laid before, and approved by resolution of, the House of Commons.
Where any arrangements have effect by virtue of this section, no obligation as to secrecy shall prevent the Board or an authorised officer of the Board from disclosing to any authorised officer of the government with which the arrangements are made such information as is required to be disclosed under the arrangements.
Where arrangements with the government of any territory outside the United Kingdom are specified under any Order in Council which—
the Order shall notwithstanding the repeal of that section by the Finance Act 1975, remain in force and have effect as if any provision made by those arrangements in relation to estate duty extended to inheritance tax chargeable by virtue of section 4 above; but the Order may be amended or revoked by an Order in Council made under this section.