Gareth Southgate has defended the Football Association’s under-fire technical director, Dan Ashworth, over allegations that the governing body orchestrated a “sham” inquiry into the Mark Sampson affair and tried to cover up an allegation of racism.

Ashworth, one of the FA executives at the centre of the Sampson controversy, has been accused by the Professional Footballers’ Association of overseeing an inquiry that was “not a genuine search for the truth” and “designed to close down the complaint and absolve Mark Sampson”.

It follows the revelations that Ashworth and the FA human resources director, Rachel Brace, held an internal review that cleared the now-deposed England Women’s manager of making an allegedly racial comment to Drew Spence at the 2015 China Cup without the two FA executives speaking to the player in question, or any of the potential witnesses, and without watching a video recording of the relevant meeting.

The issues that have led to the PFA sending an official complaint to the FA, describing it as “a sham which was not designed to establish the truth but intended to protect Mark Sampson”, will form part of a parliamentary hearing on 18 October when the culture, media and sport select committee summons a number of senior FA officials, including the chief executive, Martin Glenn, for an explanation. Eni Aluko, the first player to make a complaint against Sampson, will be giving evidence along with another former England international, Lianne Sanderson. Ashworth’s conduct is bound to feature prominently and Southgate said he was willing to defend his colleague’s reputation.

“My experience of the way he [Ashworth] wants to work, and the environment he has created for us coaches at St George’s Park, is that he would always want to work ethically and in the right way,” Southgate said. “I am certain of that and he wouldn’t take his responsibilities lightly. I think he’s very aware of the diversity of players in all of our teams. My view is that he is always very conscious of how we work in that field and would definitely be aware of the sensitivity of that subject. I don’t believe that he would want to cover something up.”

Sampson was sacked last week after a flurry of publicity prompted the FA to look more closely into an old safeguarding report that showed he had “inappropriate and unacceptable” relationships with players when he was coaching at Bristol Academy, his previous job. Southgate, who said he did not know at the time that Sampson was the subject of a safeguarding investigation, was reminded that he had described his former colleague as an “excellent character” when the stories first emerged about allegedly racial comments. Aluko claims Sampson told her to be careful her Nigerian relatives did not bring Ebola to Wembley, whereas Spence, a mixed-raced player, has told the reopened independent inquiry that her former manager asked her how many times she had been arrested. Sampson denies the allegations.

“I think you speak as you find with people, and my dealings with Mark have always been very good,” Southgate said. “Obviously I am dealing in coaching meetings and seminars and it is a different environment to the team. But I am not going to stand here and take back what I said. I found him to be a good character.”

However, Southgate did add that Sampson ought to have known he was in “potential danger” when it comes to manager-player relationships in football. “If we are looking at safeguarding guidelines, everybody on their [coaching] qualifications [should know] that’s part of it. Every two or three years you have to keep that part of your qualification updated. There would be a section in there around the influence of a coach and what you have to watch out for.”