A Labour candidate whose suspension for alleged Holocaust denial led to the head of the party's disputes panel quitting has apologised and "accepted an offer" of anti-Semitism training.
Alan Bull was due to stand for election in Peterborough but faces investigation over a 2015 Facebook post.
Christine Shawcroft resigned from the party's disputes panel after it emerged she initially opposed his suspension.
Mr Bull said sharing the post was a "bad mistake".
In a statement, he said he re-posted the article suggesting the Holocaust was a hoax to a "closed group" of Facebook "friends" to "invite discussion and debate".
He said he had been "quite new to FB (Facebook) and ignorant of the fact that sharing controversial articles in this way would be viewed as anti-Semitic".
"I'm not an anti-Semite, I am not a holocaust denier – I support equal rights for Palestinian people," he said.
"I fully accept advice received since 2016, that occasionally at that time I exercised poor judgement when posting – even if it was to a closed group of FB friends, and I apologise profusely for pain suffered which I certainly did not intend."
Ms Shawcroft quit last week after it emerged she had opposed his suspension.
She said she had not been aware of the "abhorrent" Facebook post.
Mr Bull's actions are currently being investigated by the Labour Party, but he said he had "accepted an offer [of] anti-Semitic training, as advised by Baroness Chakrabarti, [whose] report states that in the event of a member being found in breach, the NCC (National Constitutional Committee) should be encouraged to consider the greater use of a wide and creative range of sanctions."
He expressed his "deep regret" regarding the social media post, and said: "I have not denied the holocaust at any time in my life and agree that doing so would be anti-Semitic."