‘I did what was right’: Liberal rebel Fiona Martin on the change that sank the religious discrimination bill

There were five Liberal MPs who crossed the floor to protect LGBTQ+ students against discrimination but the one who tipped the balance is now being accused of breaching a commitment not to defeat the government.

It was the member for Reid, Fiona Martin, who most shocked her colleagues when she crossed the floor shortly before dawn on Thursday to add protections that would result in the entire religious discrimination bill being shelved.

The rebel group of five MPs was built on the foundation of Bridget Archer and Trent Zimmerman, who had publicly warned they could not back the bill unamended, but Martin was the decisive third vote that guaranteed the amendment's success.

Dave Sharma honoured his commitment that he would not be the casting vote, but if the dam wall broke and the government lost a third MP, he would be the fourth to cross.

Katie Allen's vote was tied to Sharma's on the understanding the Liberals could use a rebellious streak to try and hold their under threat blue-ribbon seats of Higgins and Wentworth.

On Friday the defence minister, Peter Dutton, said that Scott Morrison was "frankly misled" about how unnamed MPs would vote on amendments during the religious discrimination bill debate.

The crucial vote on Thursday forced the government to shelve its religious discrimination bill, as conservatives within the Coalition and Christian lobby groups argued the LGBTQ+ student amendment to the Sex Discrimination Act (SDA) would prevent schools setting their own ethos.