The Football League has said it is passing to police a file with documents relating to Bob Higgins, the former Southampton youth coach named in connection with allegations of historical sexual abuse of children.

Former players have alleged they were abused at Southampton, where Higgins worked with youngsters in the 1980s. More than 20 police forces across the UK are investigating allegations of historical abuse in youth football, with an NSPCC hotline having taken hundreds of calls since the former Crewe Alexandra defender Andy Woodward waived his right to anonymity to tell the Guardian he had been a victim of sexual abuse.

The EFL said the file it was sending to police to assist with Operation Hydrant, which concerns historical child sexual abuse allegations, would include a letter which warned all 92 league clubs about Higgins in 1989. The Guardian passed the letter to the league, which said on Tuesday that an investigation had concluded it was not related to abuse allegations.

“Upon being made aware of its existence, we began a search of our archives in order to locate the relevant file from that time,” a statement from the league said. “The file has now been found and arrangements are in place for this to be passed to Operation Hydrant in case it is relevant to any ongoing investigations.

“The letter referred to above was issued to all 92 clubs as a result of The Bob Higgins Soccer Academy writing to them on or around the 14th April 1989 offering their services, which operated outside the licensed criteria that applied at that time, in respect of avoiding the maximum time boys were able to travel to clubs licensed ‘Centres of Excellence’ as well as the number of hours they could train.

“The Football League’s response was sent with the support of both the FA and the ESFA (English Schools FA) who had been involved in discussions about the status of The Bob Higgins Soccer Academy outside the licensed criteria in the preceding months. As the file will now shortly be with the police, no further comment will be made by the EFL at this time.”

Higgins left Southampton in April 1989 – the same month the letter was sent. In 1992 he faced charges of sexual offences against boys but was cleared on the direction of a judge.

He went on to work with youngsters at Peterborough and also worked in men’s football for non-league clubs.

Higgins was investigated in 1997 in the Channel 4 Dispatches documentary. He sent a one-and-a-half-page response to Dispatches in which he denied all allegations of abuse.

The EFL added that it was “fully committed to providing whatever assistance is requested by the FA, Operation Hydrant and/or clubs with regard to the historic sexual abuse allegations, as well as undertaking a full review of our current regulations and safeguarding policies”.

Southampton have said they are “committed to working together” with police to investigate any historical allegations.

Peterborough’s chairman, Darragh MacAnthony, has said: “Peterborough United will help the police, the FA, PFA and all other governing bodies of football in their investigations into historical child sex abuse claims.

“If anyone is found guilty of any offences, we hope they will be severely dealt with by those authorities in a quick and timely manner.”