Labor has come under fire over the dual citizenship saga, after Senator Katy Gallagher was found to have breached the eligibility rules under Section 44 of the Constitution by the High Court on Wednesday.

Despite attempting to renounce her British citizenship, the High Court ruled that the Labor Senator missed the deadline, and was a dual citizen at the time of her election.

Ms Gallagher said she was “deeply disappointed” with the outcome, making her the 11th politician to be booted out of Parliament.

“I have always performed my duties to the ACT community with honesty, integrity and a desire to make Canberra and Australia a better place for all of us,” she said in a statement.

“I have always acted on the best available legal advice, which at all times, indicated that I satisfied the eligibility requirements under the Constitution. However, today the High Court has made its decision, and I respect the outcome.”

Despite her abrupt exit, she made it clear her time in politics is far from over.

“To have my place in the Senate end like this today (Wednesday) is very deeply disappointing but I believe that I have more to contribute to public life and I will take the time to talk with Labor Party members on how I can do this over the months ahead,” she said.

Ms Gallagher’s replacement is likely to be David Smith, a director of union Professionals Australia, he is second in line on Labor’s ballot paper.

There are three additional Labor members of the House of Representatives who are expected to see the same fate: Susan Lamb in the seat of Longman, Queensland; Justine Keay in the Tasmanian seat of Braddon; Josh Wilson in the seat of Fremantle, WA – all of whom tried to renounce their British citizenship but missed the deadline ahead of their election – along with the Centre Alliance’s Rebekha Sharkie in the seat of Mayo, SA.

Attorney-General Christian Porter has taken the hard line, stating that the decision was a “crisp and crystal clear clarification of the law”, and called for the MPs resignation today.

“If a person is a dual citizen of another country after the date of close of nominations, then that person is ineligible to sit in the common Wealth parliament,” Mr Porter said.

“And those four (Labor) people must resign. They must resign today. (Opposition Leader) Bill Shorten must require the resignation of those three Labor members today, and that must occur before close of business today.”

In contrast to the Liberal party’s action on suspected constitutional breaches, which saw the resignation of Barnaby Joyce, John Alexander, Stephen Parry, Fiona Nash, and Matt Canavan, Defence Industries Minister Christopher Pyne said the opposition leader was dragging his feet, and that he should “do the right thing” regarding the three Labor MPs.

“By contrast, on the Labor side, when Bill Shorten was faced with similar issues, he circled the wagons, behaved like a trade union leader trying to avoid accountability and transparency, and today we’ve seen the outcome of that, where three of his members have been ruled ineligible, in effect, by the decision, this unambiguous decision, of the High Court,” said Mr Pyne.

“The idea that this leaves any room for manoeuvre on the Labor side is quite frankly laughable.”

But the question remains: given the multicultural nature of Australia as a nation, why not change the Constitution to allow for dual citizenship?

This would require a referendum, which could very well eventuate if the argument gains enough momentum.

The fate of the Labor MPs’ coupled with the resignation of Perth’s Labor MP Tim Hammond will see five by-elections take place, a very costly exercise.

Meanwhile it is set to be one election after another with the Victorian state election expected to take place before the end of 2018 and in NSW next March, while Prime Minister Malcolm Turnbull said yet again on Wednesday that he wanted to call a general election in the first half of 2019.