Andy Bull has left his post as a freelance qualifications consultant for the National Council for the Training of Journalists after a past conviction for downloading child porn was uncovered.

The training organisation was unaware of his three-month jail term in 2004 for the offence until it was brought to their attention by holdthefrontpage.co.uk. It regards the lack of disclosure as a breach of trust.

He was recently appointed co-ordinator of a consultation on the future role of press photographers and photojournalists.

A spokesperson for the NCTJ said: "It was brought to the attention of the NCTJ yesterday that Andy Bull, a freelance consultant, served a prison sentence in 2004 for convictions related to internet child pornography.

"We regret that these matters were not brought to our attention by Andy Bull and under the circumstances have decided it is not appropriate for him to have a future involvement with the NCTJ."

Freelancers are commonly employed through recommendation and work record, and he would not have been asked about previous convictions, which in this case would not be "spent" for seven years.

But he failed to disclose his conviction, from January 2004, when he was found guilty on four counts of making an indecent photograph of a child and was sentenced to four three-month jail terms, which ran concurrently.

Andy, who has been open in the past about what happened, previously wrote about what he had done in a 4,500-word piece for The Times Saturday Magazine, and his wife wrote a long piece in The Guardian.

He had been questioned by police as part of Operation Ore, a global operation which led to many arrests.

He told holdthefrontpage: "I look back with shame and regret at the events that led up to my arrest in 2003.

"In the intervening years I have been able to rebuild my family life and embark on a new phase in my journalistic career."

His professional track record includes the Daily Mail, the Independent, Mail on Sunday, The Times, AOL, time at Conde Nast and then the Sunday Express, from which he resigned as deputy editor when first accused of the offences in March 2003.

His photography role would have seen him working with editors, picture editors, photographers and trainers to seek their views on the way forward for industry training.

He has run refreshers designed to get candidates up to speed for their National Certificate Examination, and has been an examiner for their Newspaper Practice papers.

He said: "My involvement in journalism training and as a freelance consultant for the NCTJ has been an enormous privilege and an opportunity to give something back to the profession."

He took on a training role with the NCTJ after his work as a core tutor on the Periodical Training Council-accredited Post-Graduate Diploma in Magazine Journalism run by PMA Training.

He developed new qualifications after doing consultancy work on NCTJ syllabuses.