Sir Oliver Popplewell, the former judge who conducted the inquiry into the Bradford City disaster, has described as "highly suspicious" Stafford Heginbotham's history of major fires but insisted that a new investigation would clear the club's then chairman of anything sinister. Popplewell also defended his 1985 inquiry after the Guardian showed him documents detailing that West Yorkshire police considered it a "seat of the pants affair" with a "severe pruning" of witnesses.

The documents raise serious questions about the way the inquiry was conducted, with senior police officers from the West Yorkshire, Humberside and South Yorkshire forces concluding it used a “minimum number of witnesses” and there was a deliberate strategy in place to “save time”.

Other paperwork from a preliminary hearing chaired by Popplewell on 23 May 1985, 12 days after the fire, shows the witness testimony was expected to run for 10 days. As it was, it lasted five. The hearing set out some of the ground rules for the inquiry, which started on 5 June, and these state that “rules of evidence would not be strictly complied with” and “hearsay would be acceptable to summarise evidence and save time”.

Popplewell, in a lengthy interview with the Guardian, rejected any criticism of his work and accused Andy Burnham, the shadow health secretary, of "climbing on a bandwagon" by calling for a new inquiry during an election.

“If we had it for 100 days the evidence wouldn’t have been any different,” Popplewell said. “We had all the evidence that was available. Except these previous fires. We had nothing else and there wasn’t anything else. It was all looked into by the fire people. The actual public hearing took only five days but we went back to the Home Office and had more evidence and we produced our inquiry in July. If we had wanted to have an inquiry like the Saville inquiry [into the events of Bloody Sunday in Derry in 1972], which lasted five years, I’m sure we could have done but we didn’t see any need to.”

The inquiry has come under scrutiny because of Martin Fletcher’s book about the tragedy that killed 56 people, including his brother, father, uncle and grandfather, when the timber stand at Valley Parade caught fire during a game against Lincoln City. Fletcher, who was 12 at the time and made it out of the inferno, believes the whole system was inadequate and asks why it was not made known to Popplewell that Valley Parade was the ninth major fire at business premises owned by or connected to Heginbotham, or that the then chairman had severe financial issues.

On 2 May 1989 there was a high-level meeting at the headquarters of Humberside police, involving its assistant chief constable, Allan Charlesworth, and Chief Inspector Brown of the West Yorkshire force. Charlesworth was formerly a superintendent in West Yorkshire and the meeting was set up because he and Brown had direct experience of the Bradford fire and could advise South Yorkshire police, dealing with the aftermath of the Hillsborough disaster, about the way Popplewell conducted his inquiry.

Superintendent David Nettleship’s two-page memo for South Yorkshire reports that: “Despite the circumstances, the Bradford inquiry only lasted for seven days, and both Mr Charlesworth and Chief Inspector Brown emphasise that the manner in which tribunals deal with evidence is entirely different to a court of law. Once a witness is able to verify a particular point, the inquiry then moves on to the next subject, with a result that there is a ‘severe pruning’ of witnesses in order to prevent duplicity [sic]and therefore save time.

“The Bradford tribunal was described as very much a ‘seat of the pants’ affair – quite informal and (to repeat) the minimum number of witnesses required to verify a specific point.” Nettleship, writing an account of the meeting for one of his chief superintendents, says the comments “confirm what we have already learned ourselves”.

Popplewell said it was “nonsense” to question his verdict that it was an accidental fire. “I’m quite satisfied we arrived at the right conclusion. This [publicity] all sparks from the previous fires and I can understand that because it is highly suspicious. But the truth is, when you analyse it there is absolutely nothing to it.” He added: “I may be proved quite wrong but I should be absolutely astonished.”

Heginbotham died in 1995. He received payouts totalling £27m in today’s terms, according to Fletcher’s book (Fifty Six – The Story of the Bradford Fire; Bloomsbury Sport) and the author’s mother, Susan, is quoted as saying she never believed what happened at Valley Parade was an accident. “I don’t think Stafford intended for people to die. But people did. All because he went back to the one thing he knew best that would get him out of trouble.”

Burnham has said the last inquiry was "completed with undue haste" while Matt Wrack, the general secretary of the Fire Brigades Union, and Nigel Adams, one of the country's prominent experts in fire forensics, have said a new investigation should happen.

Popplewell also believes an investigation is necessary and, in a pre-interview letter to the Guardian, he writes that nobody at the time alerted him to the possibility of there being anything sinister. “If we had known about the previous fires at his premises we would have asked the authorities for their views in order to satisfy speculation.” There was no evidence, he said, of arson. However, Popplewell also leaves himself to open allegations of being misinformed on several points. Among them, he initially calls Bradford’s ground “Villa Parade” and also repeatedly states that the fire was in the second half when it was actually five minutes before half-time.

Popplewell also states that Heginbotham “immediately put his hands up and said: ‘Look, I’m entirely responsible, or the club is entirely responsible, for this.’ He said: ‘It’s my fault.’”

Fletcher responded on Sunday by saying that was patently untrue, pointing out that the police, the injured and relatives of the bereaved had to pursue a court case against Bradford to prove the club’s liability. “To suggest the man who defended his club in Leeds High Court until February 1987 and consistently denied any responsibility until then, somehow accepted liability from the outset is a clear nonsense.”