Senator Anning said that while he was opposed to violence of any form, “what it highlights is the growing fear within our community, both in Australia and New Zealand, of the increasing Muslim presence”.

The response on social media was fast and furious but a Sydney doctor Kate Ahmad and a Melbourne author Harris Sultan decided to do more than tweet.

Separately and an hour apart, they started petitions requesting Senator Anning be removed from parliament. For both, it was their first petition. Now merged, the petition is by far the largest in Australian online petition history – and even individually Dr Ahmad’s had eclipsed the Sydney Opera House horse racing advertising petition in 2018.

Executive director of change.org Sally Rugg said it was not just the petition with the most signatures since the platform began but it was also the fastest-growing. Almost 250,000 people signed up in the first 18 hours. She said the petition was a lightning rod for those who did not support what she described as anti-Muslim sentiment in some sections of the media and parliament.

Dr Ahmad was shocked by the senator’s remarks. Her petition said:

“Senator Fraser Anning has no place in the government of our democratic and multicultural country. We request that he be expelled from his position as senator, and investigated by law enforcement agencies for supporting right wing terrorism.”

She has been blown away by the response.

“It shows that Australians don't tolerate extreme hate speech and the attitude that Senator Anning has displayed,” she said.

Dr Ahmad, 39, is a staff specialist neurologist and director of physician training at Royal North Shore Hospital. She grew up in Hobart and went to a small Catholic school.

Although she is thrilled by the response, she understands there is no mechanism for expelling politicians unless they are criminals or dual citizens, but she wanted to make a point.

“It’s to make clear that this kind of hate speech won’t be accepted by the community or the country as a whole, that there are repercussions for this behaviour," she said.

“Politics has degenerated to the point where extreme views have become mainstream and have a veneer of legitimacy. It’s a problem we have an elected member of parliament like this and he must take responsibility for his actions.”

Her co-petitioner is Harris Sultan, 35, an ex-Muslim, author and activist who came to Australia from Pakistan. He was motivated to start the petition because he believes it’s acceptable to argue about ideologies, "but we cannot be bigoted towards people".

"We can’t support comments or views that demonise entire communities,” he said.

University of Sydney political sociologist Professor Ariadne Vromen said people did not sign petitions such as these without care or thought.

“Petitioning has become a routine way to express a point of view and have a voice which people don’t feel they have any more,” she said.

Her research on change.org shows 75 per cent of signatories have only ever signed one petition and the remainder tend to sign only in the area they care about.

University of Sydney constitutional law expert Professor Anne Twomey said that unless the Parliamentary Privileges Act 1987 was amended, there was no possibility for a member to be expelled – and as she pointed out, it was unlikely to be amended in the few sitting days left before the expected election.

“Disqualification is a different matter ... it includes disqualification of any person who is 'attainted of treason, or has been convicted and is under sentence, or subject to be sentenced, for any offence punishable under the law of the Commonwealth or of a State by imprisonment for one year or longer'. It does not cover behaviour likely to bring the houses into disrepute (which is still grounds for expulsion in the NSW Parliament),” she said.

Dr Ahmad said: “It may be that we now need to have some kind of provision to exclude parliamentarians who incite or encourage extremism.”

Senator Anning’s office has been approached for comment.