A Royal Mail employee who blew the whistle on racism at his workplace but was then sacked is believed to have won £100,000 compensation in an employment tribunal.

Abdul Musa, a former worker at a RM depot in Blackburn, reported racist behaviour at the depot to managers, which resulted in one worker being sacked and others disciplined.

However, following his complaint, Musa was victimised by remaining colleagues as managers failed to protect or support him, the tribunal heard. He was then sacked in 2007 and claimed both race discrimination and unfair dismissal.

The tribunal found failings in the employer’s internal investigation, which it said had not examined complaints that union representatives from the Communication Workers Union had backed an unofficial campaign to have Musa sacked by fabricating evidence.

The tribunal judgement said RM’s managers had viewed Musa as “a problem” in terms of the negative reaction of other workers, which could only be solved by dismissing him.

The Equality and Human Rights Commission (EHRC), which funded Musa’s legal representation, called RM’s internal inquiry into the complaint “shambolic”.

John Wadham, general counsel for the EHRC, said: “The Equality Act protects people from being victimised for making complaints about any form of discrimination in the workplace. It also says employers have a responsibility to take complaints seriously and to put a stop to discrimination.

“The fact that his colleagues were acting unlawfully was not enough to stop them from victimising Mr Musa. People facing discrimination also need an advocate, such as the EHRC, to make sure that the law is obeyed.”

A spokeswoman for the union said there were no charges against the CWU or its representatives in the case. “We have a long standing record of successfully representing our members in cases of this nature and want to see racism stamped out in all workplaces,” she added.