8(1)For purposes of the provisions of this Act relating to close companies, including this Schedule, a " trading company " is any company which exists wholly or mainly for the purpose of carrying on a trade and any other company whose income does not consist mainly of investment income, that is to say, income which, if the company were an individual, would not be earned income; but for this purpose any amount which is apportioned to a company under this Act, and any such amount as, in relation to a company to which section 245 of the [1952 c. 10.] Income Tax Act 1952 applied, is directed by any enactment to be treated as investment income, shall be deemed to be income of the company and to be investment income.
(2)For the said purposes a company is to be treated as a " member of a trading group " if, but only if—
(a)it exists wholly or mainly for the purpose of co-ordinating the administration of a group of two or more companies each of which is under its control and exists wholly or mainly for the purpose of carrying on a trade ; or
(b)it is under the control of another company resident in the United Kingdom and not itself under the control of a third company, and it exists wholly or mainly for the purpose of a trade or trades carried on by that other company or by a group which, consisting of that other company and a company or companies also under its control and resident in the United Kingdom, exists wholly or mainly for the purpose of carrying on the said trade or trades:
Provided that a company shall not be treated as a member of a trading group by reason of any company having the control of another, if that control is exercised through a company which is not resident in the United Kingdom or through a company whose control depends on a holding a profit on the sale of which would be treated as a trading receipt of the company.