The show's producers are examining the programme tapes
Major Ingram's £1m win was edited out of Saturday's programme while police investigate claims he may have been aided by coded coughing in the audience.
But college lecturer Tecwen Whittock said he and several other audience members had innocently coughed during the major's £1m round.
Mr Whittock said it would have been hard to differentiate between different coughs.
Major Ingrams has denied cheating and threatened legal action against production company Celador, who have yet to pay out his £1m prize.
The police were called into investigate the programme tapes after producers feared Major Ingram may have received a signal from the audience.
Major Ingram, 38, became only the third person in the show's history to scoop the £1m prize, but his win has been marred by the subsequent claims.
Mr Whittock, 51, from Whitchurch, Cardiff, said he had coughed naturally and the noise could not have had anything to do with the alleged controversy surrounding the jackpot win.
Mr Whittock, from Whitchurch, Cardiff, said his cough was brought on by the cold studio and he added a number of audience members had been coughing during filming.
Mr Whittock said none of the contestants waiting in the audience had any interest in helping someone win the big prize.
"Yes, I did cough while the major was in the hot seat - but many other people in the studio did too," said the Pontypridd College lecturer.
"There were 200 people in there and it was quite cold. I heard many people coughing and can't believe the major could have been helped in such a way."
He added: "I certainly wasn't trying to help him. It wasn't in any of the contestants' interests to help him - we wanted him out so we could have our go."
Mr Whittock, head of Pontypridd College Business School, later went on to win just £1,000 on the show.
The lecturer said he could not understand the intense speculation over "coughing clues".
"The first I knew something was wrong was when the producers called to say my episode had been brought forward.
"Everything seemed fine at the time - Chris Tarrant was delighted he had won the £1m and we all clapped and cheered for him.
"It would have been extremely difficult for him to distinguish his accomplice from all the different people coughing in the audience.
"But if what is being said is proved he should not be paid the prize because cheating is wrong."
The UK's two previous Millionaire? jackpot winners are Judith Keppel and David Edwards.