The secretive process to elect the lord mayor of London was thrown into disarray after senior officials in the City raised questions over whether one of the leading candidates was eligible for the role.

Nick Lyons, chair of the insurer Phoenix and board member of Bupa, is one of the final two candidates seeking to become the City’s 694th lord mayor in 2022, according to several people familiar with the situation.

But his application has led to objections from some City leaders after they discovered that he holds an Irish passport. They believe the rules require the lord mayor to be a British subject. These people said the issue of Lyons’ Irish citizenship has held up this year’s election for the post of lord mayor in 2022.

Although largely ceremonial, the holder of the 832-year-old role represents the City of London in meetings with political and business leaders around the world, giving them a key “soft power” position in UK foreign relations.

Lyons is competing for the role against fellow alderman Tim Hailes, who would become the first openly gay lord mayor in the history of the City if chosen.

Hailes previously stood for the 2019 mayoralty, an election that was marked by controversy after it emerged that he was asked questions by the selection committee relating to his sexuality. He passed the interview, but his candidacy was deferred given the time demands of a new company directorship.

The lord mayor is elected by the City of London Corporation’s Court of Aldermen — a group of 25 mostly men that represent different wards of the Square Mile. A candidate has to be an alderman with elections usually held the year prior to the winner assuming office the following October.

The 2013 Act Of Common Council, which defines aldermanic eligibility, states that a candidate needs to be a “British subject” and “an able and sufficient citizen and freeman of the City of London”.

After questions over the eligibility of Lyons were raised in an aldermanic meeting in May, the City of London Corporation — the local authority for London’s financial district — had to ask its top lawyers to consider whether Lyons, as an Irish citizen, was allowed to proceed with his application.

The opinion given was that existing laws are such that a non-British citizen can hold the post, according to people familiar with the matter. Eligibility to be alderman or lord mayor should be based on the qualifications to be a freeman of the City, which under EU law was extended to citizens of the EU. The laws still apply post-Brexit.

The argument shines a light on the arcane nature of many of the City of London’s rules and processes, which have been tweaked and overwritten multiple times since the first charter was granted for the area by William the Conqueror in 1067.

The City of London Corporation confirmed to the Financial Times that it had consulted four senior law officers for their opinion on the dispute.

In a statement it said: “They are unanimous: citizens of Ireland are not disqualified from standing as a candidate for the office of alderman in the City of London. This is entirely consistent with the latest regulations and legislation from the government which makes clear EU citizens are free to vote and stand for local elections.”

Another City insider said that Lyons had also obtained legal advice that said that he was able to claim British citizenship given his father was from Northern Ireland. Lyons did not respond to a request for comment.

However, these views have not stopped senior Corporation members raising concerns given how these rules have been applied in the past as well as what the decision might mean in the future.

One senior City leader with knowledge of the situation said that he questioned how the legal opinion sat alongside the rules laid out by the Act of Common Council. “I struggle with this as it seems black and white to me otherwise we would have been telling everyone that you didn’t need to be a British citizen before.”

Another, who has also flagged doubts over Lyons’ eligibility, said: “It’s one of the oldest public offices in the land so can’t be taken lightly. [The City is] trying to sweep this under the carpet.”

He added that the controversy came ahead of a period of turnover for the exclusive group of aldermen, with up to six posts needing to be filled in the next year given retirements, illnesses and the death of banker Roger Gifford last month.

The City of London has faced accusations of being an old boys’ club given that just four of the 25 aldermen that make up the senior leadership are women.

The Court of Aldermen, which is presided over by William Russell, the incumbent lord mayor, is expected to reconvene next week to select a preferred candidate, according to one person familiar with the matter.

The aldermen include former lord mayor Sir Andrew Parmley, who is chair of the nominations committee, and his deputy and former Barclays executive Sir Peter Estlin. Others include former lord mayors Sir Charles Bowman and Sir Alan Yarrow, banker Prem Goyal and QCs Lady Patricia Scotland and Gregory Jones.

Russell, who took over in 2019 and is the fifth member of his family to have held the position, had his tenure extended by a year due to the pandemic. He will be succeeded by Vincent Keaveny.