A plan to change Northern Ireland's electoral boundaries that was quashed in court on Thursday cost nearly £800,000, it can be revealed.
The review by Northern Ireland's Boundary Commission in 2018 cost £798,000 and had recommended reducing the number of parliamentary constituencies here from 18 to 17, as part of a wider move to reduce UK MPs from 650 to 600.
This was quashed by the Court of Appeal, with senior judges identifying a legal failure by the body to properly consider all responses to a consultation.
They added that inadequate reasons were given for using a rule allowing the body to shift away from electoral quota requirements.
The commission's findings were challenged in court by west Belfast man Patrick Lynch, with Sinn Fein also claiming it would see some constituencies left without nationalist representation.
A spokesperson for the Boundary Commission said the 2018 review had cost £798,000 but the body would wait to read the final written judgment from the Court of Appeal before commenting further.
Sinn Fein's MP for Mid Ulster, Francie Molloy, said the commission's suggestions would have left thousands of nationalists disenfranchised.
"The court found that the commission had misapplied the law in relation to its use of the controversial Rule 7 - which would mean that not all votes would carry equal weight," he said.
"It also found that the commission failed to give adequate reason for this.
"The court also ruled that the commission did not give equal consideration to all responses to its consultation into the proposed boundary changes and fettered its discretion in considering responses received later in the process, effectively creating a hierarchy of responses."
He continued: "These proposals created considerable anger among nationalists and, if implemented, would have led to thousands being disenfranchised.
"Today's ruling quashes these proposals and is a victory for democracy. It also clarifies the role and obligations of any Boundary Commission and ensures that any future proposed changes to the electoral boundaries will have to be fair and transparent."
Earlier proposals would have reduced the amount of MPs in Belfast to three, but the final recommendations from the commission kept the existing four seats.
Mr Lynch's lawyers said this was a sudden and radical change, and that the commission had acted unlawfully and unfairly. His legal team also claimed the commission had suddenly and radically changed its position for the final report.
Lawyers for the commission argued the changes were part of a "healthy and procedurally correct consultation process".
In May last year, the High Court held that the commission had failed to properly consider the final consultation responses, but Mr Lynch still appealed to quash the recommendations.
Mr Justice Horner said that the commission's final report was "vitiated by procedural unfairness" and concluded it should be sent back for lawful reconsideration.
This could be rendered academic, however, if new legislation at Westminster is passed which would abandon the boundary review.
Speaking after the verdict, Mr Lynch's lawyer, Eoin Murphy of O Muirigh Solicitors, said the decision from the Court of Appeal avoided any "irreparable" errors and helped to clarify the obligations of any Boundary Commission now or in the future.