100.—(1) An act is not protected if the reason, or one of the reasons, for which it is done is the fact or belief that a particular employer—
(a)is employing, has employed or might employ a person who is not a member of a trade union, or
(b)is failing, has failed or might fail to discriminate against such a person.
(2) For the purposes of paragraph (1)(b) an employer discriminates against a person if, but only if, he ensures that his conduct in relation to—
(a)persons, or persons of any description, employed by him, or who apply to be, or are, considered by him for employment, or
(b)the provision of employment for such persons,
is different, in some or all cases, according to whether or not they are members of a trade union, and is more favourable to those who are.
(3) An act is not protected if it constitutes, or is one of a number of acts which together constitute, an inducement or attempted inducement of a person—
(a)to incorporate in a contract to which that person is a party, or a proposed contract to which he intends to be a party, a term or condition which is or would be void by virtue of Article 27(1) of the 1992 Order (union membership requirement in contract for goods or services), or
(b)to contravene Article 27(2) of that Order (refusal to deal with person on grounds relating to union membership).
(4) References in this Article to an employer employing a person are to a person acting in the capacity of the person for whom a worker works or normally works.
(5) References in this Article to not being a member of a trade union are to not being a member of any trade union, of a particular trade union or of one of a number of particular trade unions.
Any such reference includes a reference to not being a member of a particular branch or section of a trade union or of one of a number of particular branches or sections of a trade union.