A week ago, Nigel Farage was toasting Reform UK’s successes in the May elections, and bragging about his prospects of becoming prime minister.

But there is a saying about a week in politics – and it has been a long seven days for the party leader, who is now facing questions over a £5m gift and his extensive property portfolio.

On Thursday, the parliamentary standards commissioner said he had opened an official inquiry into the money Farage accepted from the crypto billionaire Christopher Harborne.

Farage is also facing questions about a £1.4m house he bought in Surrey in 2024, the purchase of which took place in the weeks after accepting Harborne’s gift.

Farage appears to either own or live in five properties. The house in Surrey is the one that has come under scrutiny this week.

The Grade II-listed detached home, on a site of historic interest and with substantial acreage, is listed on planning documents from 2025 as being occupied by its new owner and not intended for rental.

Farage also appears to have filmed videos there on the Cameo platform in the last two years, and a neighbour said security had been installed at the property some time after he bought it.

Reform sources, when asked whether Farage used the Surrey house as one of his residences, said he would not say where he spent his time, on the basis of security advice, as the danger to him was too high already.

The £1.4m home is in addition to a house in Downe in Kent, which Farage has previously talked about as his home.

He gave an interview to UnHerd in March 2024 about his connection to the area, with the headline: “The village that made Nigel Farage”.

The Reform leader also said during the local elections campaign that he lived for “half the week” in Clacton, his constituency, where he initially claimed to have bought a house. It was later revealed that the £885,000 property had been bought outright by his partner, Laure Ferrari.

After the Guardian’s reporting on the £5m gift from Harborne, there have been renewed questions about the source of financing of Farage’s properties.

The Reform leader has maintained the £5m was given on a no-strings-attached basis by the businessman for the purposes of ensuring Farage’s security for life.

But on Thursday, Farage appeared to undermine his own explanation, saying in an interview with the Sun it was a “reward” for campaigning for Brexit for 27 years.

Farage insists the £1.4m home has nothing to do with the Harborne money, with sources saying the negotiations to buy the Surrey property took place a few weeks after he left the ITV series I’m a Celebrity … Get Me Out of Here, having been given a £1.5m appearance fee.

The sources said an offer was accepted in March and proof-of-funds along with anti-money-laundering checks were completed before Farage received the Harborne gift. They also stressed that all correct stamp duty had been paid, which would amount to about £125,000 on the purchase of a second home of that value.

Alongside Farage accepting the gift from Harborne and then becoming an MP in 2024, it appears to have been a busy year for his property portfolio.

The Reform leader also owns two properties on the Kent coast through his company Thorn in the Side – one bought in 2020 for £500,000 and a second in 2023 for £575,000.

The second was granted planning permission to be demolished and rebuilt in 2024, not long after the Surrey purchase.

The house used by Farage in Clacton was bought in November 2024. The Reform UK leader first said he put the property in his partner’s name for security reasons, before saying she had bought it with her own money.

However, more recently, Ferrari has declined to say where she got the funding for the Clacton house.

Asked on Thursday about the purchase of the £1.4m property, which was first revealed by Sky News, a Reform UK spokesperson said: “The relevant chronology is straightforward. The offer and purchase process for the property commenced before the gift.

“Mr Farage had already passed proof of funds and the relevant checks before receiving the gift. The purchase was therefore already proceeding independently of it.”

However, Labour has already called on the Reform leader to give a full breakdown of what the £5m from Harborne was used to pay for.

Anna Turley, the chair of the Labour party, said: “Nigel Farage has repeatedly dodged questions on his multimillion-pound ‘gift’.

“Now we can see why – this totally stinks. Farage must urgently come clean with the public as to what this £5m was used for and why he failed to declare it.”