The Football Association was steeling itself for an examination of how the Mark Sampson scandal was handled after a month of tribulation which began with claims of racism revealed in the Guardian, ended with the sacking of the England manager over safeguarding allegations.

The governing body’s chief executive, Martin Glenn, said the decision to terminate Sampson’s contract was obvious after he became aware of the “full detail” of inappropriate relationships the Welshman had with female players while he was manager of Bristol Academy.

It is the second time in less than a year that Glenn has been forced to hold a hastily convened press conference to explain the departure of an England manager for off-field reasons. Questions about whether due diligence was done in the hiring of Sampson are bound to be asked, particularly as it comes almost 12 months to the day since Sam Allardyce departed after a newspaper sting.

It is understood claims made by the former England striker Eni Aluko to the Guardian of bullying, harassment and racial remarks prompted a whistleblower outside the FA to urge Glenn to read the full report into safeguarding allegations made against Sampson.

The allegations relate to Sampson’s time at Bristol Academy, where he worked first with 10- to 16-year-olds at the centre of excellence and later as the senior first-team coach. The allegations were made by more than one player and are said by the FA chairman, Greg Clarke, to range from the “trivial to the very serious”.

Timeline The final days of Mark Sampson as England manager Show Hide Bullying claims emerge It emerges Eni Aluko, the England and Chelsea forward, made claims of bullying and harassment against Sampson and his staff in May 2016. An FA investigation, concluded in March 2017, cleared Sampson and his staff of wrongdoing but it emerges Aluko was paid a £80,000 settlement in a confidentiality agreement, which the FA insisted was to avoid disruption to England’s Euro 2017 campaign Aluko allegation Details become public of an allegation made by Aluko, claiming Sampson made a remark towards another player with 'racial and prejudicial connotations'. Sampson is alleged to have made reference to the number of times a player had been arrested Another Aluko allegation Aluko alleges Sampson made a racist comment to her before an England game. After telling Sampson she had relatives coming from Nigeria to watch the international, Aluko claims Sampson replied: 'Well make sure they don’t come over with Ebola' Sampson breaks public silence Sampson speaks publicly for the first time about the allegations and says his conscience is clear: 'This has not been a nice situation for anyone' A contradiction in evidence? Sampson appears to contradict evidence he gave to the inquiry when he tells a press conference he cannot recall ever having a conversation about Ebola with Aluko Drew Spence comes forward The Guardian reveals the FA is giving serious consideration to launching a new investigation into the Sampson affair after Drew Spence, one of two players to allege he had made a racial remark, comes forward to tell the governing body that what Aluko has said about the England women’s team manager is true Sampson sacked Football Association chief executive Martin Glenn becomes aware of the 'full detail' of inappropriate relations Sampson had with female players while he was manager of Bristol Academy

Sampson was deemed fit to continue as England manager after the FA’s safeguarding and investigations team conducted inquiries when the allegations were first made in March 2014. Glenn, who joined the FA 12 months after that, insists he was first told of the investigation in October 2015. He read the full report only last Wednesday and later passed it on to Clarke.

Glenn admitted regret that Sampson had been allowed to occupy a position of such power and influence for almost four years. “There was a full investigation, a proper investigation, an assessment process and when the report concluded in March 2015 he was deemed not to be a safeguarding risk,” Glenn said. “However, the full report of that investigation was only made known to me last week.

“On reading it I immediately shared it with Greg and we were both deeply concerned with the contents of the report. Let’s be really clear: no laws were broken; Greg and I are not able to challenge the professional views of our safeguarding experts. We thought the conduct issues raised in the report was the problem. Mark had overstepped the professional boundaries between player and coach. We know that coaches are in a potential position of power and that position mustn’t be abused. We have to be really clear and I think we are at the FA, about what we stand for in that respect.”

On the pitch, Sampson has been the most successful England manager of recent times, his departure coming less than 24 hours after his team, semi-finalists at Euro 2017 this summer, defeated Russia 6-0 in their first World Cup qualifying match. After the first goal went in all 11 players, including the goalkeeper, sprinted to embrace him in the dugout, an orchestrated demonstration of support for the manager in the wake of the Aluko allegations.

The 34-year-old’s contract was due to expire in June 2019 but he was informed over the phone by Glenn on Wednesday afternoon that it would be terminated immediately and though there was no argument, Sampson was upset. It is understood his salary was between £100,000 and £150,000 a year and he will receive a payoff equivalent to a few months’ salary.

England rout of Russia shows on-field unity but sparks criticism from Eni Aluko Read more

Glenn promised that an investigation into claims made by Aluko that he had made racial remarks to her and another player Drew Spence, who is mixed race, would continue. That investigation, led by the barrister Katharine Newton QC, was reopened after it emerged many of the main protagonists had not been interviewed. While many of the current squad vocalised their support for Sampson, the former players Lianne Sanderson and Katie Champan said they also felt discriminated against during his reign.

FA executives had already been summoned by the government’s culture, media and sport select committee on 18 October to explain their handling of the whole situation. Glenn and Clarke, should they attend parliament, are now likely to be questioned on why they did not request sight of the full safeguarding report sooner given what prominence Sampson occupied in the women’s game.

Tracey Crouch, the minister for sport, said: “This situation is a mess and raises very serious questions about whether the historic processes that the FA had in place around the recruitment of coaches were appropriate, for something like this to have been missed. The FA are right to have taken action but reassurance is needed to make sure this does not happen again at any level of coaching.”

Sir Trevor Brooking was director of football in December 2013 when Sampson was appointed as England manager. Both Glenn and Clarke insisted standards had been raised at the FA and that Sampson would not have kept his job had they seen the full report earlier.

“We are not going to apologise for wanting to drive higher standards,” Clarke said. “Let’s look at safeguarding in sport and football, the whole culture has been ignore it, don’t deal with it, hide it, put it under the carpet, because bad things will happen. We know we can’t do that so there are plenty of people in the game that have got an unblemished record to provide a great pool for us to continue to recruit great coaches from.”

On Wednesday night Sampson was removed as a patron of Women in Sport, a charity whose aim is to empower women and girls through sport. “The charity hopes that media attention will now return to the women’s football team performance on the pitch, and that women and girls up and down the country will continue to be inspired by the Lionesses’ World Cup campaign,” read a statement.