UK Employment Law - Job Offer Question?

[khalid]

My wife works in a customer service centre which handles customer queries on behalf of a number of their clients (standard customer service outsourcing model).

She recently interviewed for an internal vacancy and received very good feedback during and after the interview. There is one other applicant.

A few days later my wife was verbally informed privately and in a casual manner that she had been successful. The other applicant was informed in the same fashion that she had not been successful on the same day.

The other applicant did not take the news well and reminded the hiring manager that the client (the company for whom they provide services) has to approve all promotions within my wife's company.

This is not strictly true. The contract between client and outsourcer merely states that the client has to be "informed" of all organizational changes.

The hiring manager has now delayed the official announcement of who will be awarded the role pending discussions with the client.

My questions:
1 - Can a third party (in this case the client) have such an influence over a hiring process according to UK law?
2 - If the hiring manager returns from discussions to advise that my wife is no longer to be awarded the role, what are her rights if any?

Many thanks for taking the time to read this.
Any help and guidance is appreciated.