47Set-off of refunds against excess profits tax.
Where after the end of the year nineteen hundred and forty-five, excess profits tax is due and payable in respect of any relevant chargeable accounting period and, if that tax were paid, a sum would (on the giving, or giving and approval, of the requisite undertakings and authorities) be payable for or on account of a post-war refund, the Commissioners may, if they think fit and if the requisite undertakings and authorities are given, or given and approved, give credit for the amount of the sum payable as afore--said, after deduction of tax at the standard rate for the year 1946-47, against the same amount of the excess profits tax which is due and payable as aforesaid, and, where credit is so given, the amount for which credit is given shall be deemed to have been paid to the Commissioners and repaid by them and the ' said undertakings and authorities shall, with the necessary modifications, have effect accordingly:
Provided that the amount deemed to have been repaid by the Commissioners shall for the purposes of income tax be treated as a payment made after deduction of tax at the standard rate for the year 1946-47.