The provisions of this section shall have effect where the Board are satisfied as respects any tax carrying interest under section 86 of this Act—
(a) that the tax is in respect of income or chargeable gains arising in a country outside the United Kingdom, and
(b) that, as the result of action of the government of that country, it is impossible for the income or gains to be remitted to the United Kingdom, and
(c) that having regard to the matters aforesaid and to all the other circumstances of the case it is reasonable that the tax should for the time being remain uncollected,
and the Board allow the tax to remain uncollected accordingly.
Interest on the said tax shall, subject to subsection (3) below, cease to run under the said section 86 as from the date on which the Board were first in possession of the information necessary to enable them to be satisfied as aforesaid and, if the said date is not later than three months from the time when the tax became due and payable, the interest thereon under the said section 86 in respect of the period before the said date shall be remitted.
Where, under subsection (2) above, interest has ceased to run on any tax and thereafter demand is made by the collector or other proper officer for payment of all or any of that tax, interest under the said section 86 shall again begin to run from the date of the demand in respect of the amount demanded: