Yet another government MP has crossed the floor to vote against the Coalition, this time backing a long-awaited integrity bill that the government opposes – and consigning Prime Minister Scott Morrison to an embarrassing defeat in Parliament.

But despite the proposal from independent MP Helen Haines winning a majority of votes on Thursday, the bill was defeated on what she blasted as an “undemocratic technicality”, as she accused the government of lacking bravery.

Mr Morrison faces an escalating backbench revolt, with now seven MPs this week thumbing their noses at his government’s position.

“They have no conviction to instigate a federal integrity commission,” Dr Haines said after wild scenes in the House of Representative earlier on Thursday.

“I remain steadfastly determined. This is not over.”

Dr Haines, who has pushed for a federal integrity body for most of her term in parliament, called for a suspension of standing orders in the House of Representatives on Thursday morning. The motion was moved so she could request her bill for an integrity commission be debated.

Her motion was surprisingly seconded by Liberal MP Bridget Archer, the Member for Bass, who has also backed such a scrutiny body.

“I don’t take this decision lightly,” Ms Archer told parliament.

“This is one of the most important things we come to this place to do … the time has gone on long enough.”

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The Coalition opposed the motion. Communications Minister Paul Fletcher, representing the attorney-general’s portfolio, said the government opposed Dr Haines’ motion because the Coalition’s own integrity commission bill would be introduced “soon” – though he did not say when.

Mr Morrison first proposed a federal integrity commission in December 2018, some 1078 days ago. Dr Haines’ bill is seen as more robust, with stronger investigative powers, than the government’s.

The vote to suspend standing orders, supported by Labor and other crossbenchers, came back 66-63 in favour. However, despite the numbers, such a motion requires an absolute majority of the 151-seat House, meaning it was successful but not carried.

It sparked a complicated set of procedural motions in the chamber, after rookie Speaker, Liberal MP Andrew Wallace, initially said the motion was successful – meaning Dr Haines’ bill would have been debated. Instead, after further votes, the motion retained its 66-64 majority – with Ms Archer’s decision to cross the floor as the deciding factor – but was ultimately deemed unsuccessful.

Veteran MP Bob Katter drew laughs when he stood to say he was “very confused” at the procedural motions.

Labor and the Greens instantly crowed that the government had lost its majority in the parliament.

Tweet from @BridgetArcherMP

Dr Haines was furious, claiming it was “undemocratic” that the rules of the House – instituted by the Coalition government – meant only an absolute majority would be successful.

“The Prime Minister and the government are standing in the way now of, not only the will of the people, but the will of the Parliament,” she told a snap press conference soon after.

“It’s absolutely clear now that this Prime Minister, this government, does not wish to instigate a federal integrity commission.”

Dr Haines praised Ms Archer as a “lioness”  and a “hero” for crossing the floor. Photographers captured the two women, walking arm in arm, out of the parliamentary chamber following the votes. Dr Haines urged other government members, who have spoken in favour of an integrity commission, to back her proposal.

“The people should call for it louder and louder until we achieve it, and in making that call perhaps we will see another person as brave, as filled with integrity, as the member for Bass,” she said.

Fellow independent MP Andrew Wilkie called Ms Archer’s position “the single bravest thing” he had seen any politician do.

Dr Haines called on the Morrison government to change its internal procedures and allow the bill to be debated if there was a similar future vote. She scoffed when The New Daily asked whether she would accept a compromise following Mr Fletcher’s commitment on the government’s own integrity commission bill.

“I didn’t come down in the last shower,” Dr Haines said.

“If the best he can come up with is that ‘we’re going to bring something soon’ … it doesn’t cut it with me.”