Nigel Farage has been dogged by questions about his finances since the Guardian revealed he received a £5m gift from a donor in 2024.

Although he insists the gift did not have to be declared, several important questions remain unanswered.

The sum was given shortly before Farage decided to stand in the 2024 general election – and it came from a Reform UK mega-donor, the Thai-based crypto-billionaire Christopher Harborne.

In recent days, Farage has attempted to deflect attention away from the gift, saying on several occasions that the money was to pay for his personal security, and that he would rather talk about it another time.

“Yeah, yeah, well we’ll talk about that any other time that you’d like,” Farage said, when asked as he celebrated Reform’s capture of its first London council, in Havering last week.

However, his political opponents have seized on the disclosure.

Among them, Kevin Hollinrake, the Conservative party chair, has said Farage was “obliged” to declare the gift.

The Reform leader may soon face questions from the Electoral Commission or the parliamentary standards watchdog, both of which have received reports related to the gift. On Wednesday, the parliamentary standards commissioner opened a formal inquiry into the gift.

Here are some of the most important outstanding queries the UK’s potential future prime minister might wish to address.

Is this the only gift he received in the run-up to the 2024 general election and beyond?

The public currently has no idea whether the £5m gift was a one-off or part of a series of large sums given by Harborne or any other donor to Farage or other senior figures in Reform.

What exactly was the money used for?

After the Guardian asked Farage about the £5m gift, he initially did not respond but then gave an interview to the Telegraph claiming the money “was given to me so that I would be safe and secure for the rest of my life”.

He suggested it was essential as he did not receive taxpayer-funded security.

There are two odd things about this claim, however.

According to Zia Yusuf, the former head of policy at Reform, Farage was receiving some public funding for his security as recently as 2025 – in October of that year he said the amount had been cut by 75%.

And he was receiving this support more than a year after he had accepted a £5m gift that was supposed to have covered his security for life.

It is still not clear how much public money was spent on Farage’s security. He said in a recent interview with Sky News that his private security “costs several hundred, many hundred thousand pounds a year”, without providing any further detail.

How was the Clacton house paid for?

An area of Farage’s personal finances that had already attracted scrutiny was how his partner, Laure Ferrari, had managed to buy an £885,000 home in Clacton-on-Sea, Essex, where Farage was elected in 2024, getting a seat in parliament at the eighth attempt. The Guardian revealed that she had bought the house in her name after Farage had claimed to be the buyer. A BBC investigation raised questions about the size of her family’s alleged wealth.

Ferrari has added to the questions surrounding this by confirming in an interview with the French newspaper Le Monde that she did not cover the full cost with any inheritance from her family.

It would have been legal for Farage to give or lend her the funds, and thereby avoid paying £44,000 of additional stamp duty on the purchase. But he said that he didn’t in September last year: “I haven’t lent money to anybody. I didn’t give her money. She comes from a very successful French family and she can afford it herself. It’s convenient, it works, and she loves it there.”

Have any other senior Reform figures received gifts?

While MPs have conventionally regarded any money from donors as something that ought to be declared, Reform has put great weight on the idea that this was a personal gift and that it was made prior to Farage’s decision to stand for parliament.

The party’s deputy leader, Richard Tice, said on Sunday: “The state wouldn’t provide the funding, and this was a personal gift based around safety and security.”

It is unclear if this has been a widespread approach throughout the party either before or after the 2024 election, with other Reform UK MPs and senior figures accepting large sums that have not been declared either to the Electoral Commission or the parliamentary authorities.

Reform UK’s media team did not respond to most of the Guardian’s questions about this article.