Businessman Arron Banks, a close associate of Nigel Farage, is understood to have hired private investigators to scrutinize Conservative Party Chairman Kevin Hollinrake, according to a report by The Mail on Sunday. The alleged surveillance operation was reportedly initiated after the Conservative Party called for an investigation into Mr. Farage concerning a £5 million donation.

Mr. Banks is understood to have instructed Precision Risk and Intelligence (PRI), a private investigations company he formerly owned, to probe Mr. Hollinrake. This comes after Mr. Banks had previously hired the same company to investigate journalists looking into the finances of the Reform UK leader.

Mr. Hollinrake has been a vocal critic of Reform UK's finances, leading Conservative attacks that included disclosures about the financial dealings of key Farage aide George Cottrell and party deputy leader Richard Tice. His letter to the Parliamentary Standards Commissioner reportedly triggered the investigation into the £5 million donation from crypto-billionaire Christopher Harborne.

When asked about hiring private investigators to probe Mr. Hollinrake, Mr. Banks stated that his team has been aware since May of a "dirty tricks campaign" waged by Conservative Party headquarters and Mr. Hollinrake against Mr. Farage. He described the situation as a "hit-job" by political rivals and certain media elements aiming to undermine Reform UK.

Mr. Hollinrake responded by calling the use of private investigators to target journalists and political opponents "sinister" and inappropriate for politics. He asserted that he was merely performing his job by asking "legitimate questions" and drew parallels to the Conservative Party's scrutiny of Labour figures.

A Conservative Party spokesperson questioned the authority under which Mr. Banks was acting and defended their stance on questioning Farage's donation and undeclared gifts. The party called on Reform UK to disclose any knowledge of the investigation and condemn Mr. Banks's actions.

PRI, the private investigations firm, declined to comment on the matter. The Mail on Sunday noted that PRI has a reputation for aggressive tactics and that the company, though dissolved after Brexit, has had former operatives continue to work on projects, particularly in high-value litigation.