A person shall not refuse to deal with a supplier or prospective supplier of goods or services on union membership grounds."Refuse to deal" and "union membership grounds" shall be construed as follows.
A person refuses to deal with a person if, where he maintains (in whatever form) a list of approved suppliers of goods or services, or of persons from whom tenders for the supply of goods or services may be invited, he fails to include the name of that person in that list.
A person refuses to deal with a person if, in relation to a proposed contract for the supply of goods or services—
He does so on union membership grounds if the ground, or one of the grounds, on which he does so is that if the proposed contract were entered into with that person, work to be done for the purposes of the contract would, or would be likely to, be done by persons who were, or who were not, members of trade unions or of a particular trade union.
A person refuses to deal with a person if he terminates a contract with him for the supply of goods or services.
The obligation to comply with this section is a duty owed to the person with whom there is a refusal to deal and to any other person who may be adversely affected by its contravention; and a breach of the duty is actionable accordingly (subject to the defences and other incidents applying to actions for breach of statutory duty.