In using collective words or nouns of multitude (Department, Parliament, Government, Committee and the like), ought we to say "the Government have decided" or "the Government has decided"; "the Committee are meeting", or "the Committee is meeting"? There is no rule; either a singular or plural verb may be used. It is true that some grammarians advise the plural when the emphasis is on the individual members and the singular when it is on the body as a whole. But that seems over-nice, and the official may be content with making sure that one or the other is followed consistently in the same document. Failure to do this is a common form of carelessness:
The firm has given an undertaking that in the event of their having to restrict production . . .
The industry is capable of supplying a11 home requirements and have in fact been exporting.
It will be for each committee to determine in the light of its responsibilities how far it is necessary to make all these appointments, and no appointment should be made unless the committee are fully satisfied of the need.
It is on the whole safer to use the plural, if only because the singular may lead to difficulty when the pronoun has to be used. They think, of a Committee, sounds more natural than it thinks.
Do not forget to make your relative pronoun correspond. If you use the singular the relative must be which, if the plural it must be who.