Rishi Sunak has apologised to the UK parliamentary watchdog after an investigation concluded that the British Prime Minister's failure to declare wife Akshata Murty's relevant business interest arose "out of confusion" and was "inadvertent".

The Parliamentary Commissioner for Standards, Daniel Greenberg, had opened an inquiry into allegations that when discussing the government's financial incentive scheme for people joining the childminding workforce, Sunak failed to declare that his wife held shares in one of six childminding agencies selected by the government to provide its new members with an enhanced financial incentive.

Sunak, 43, told the parliamentary watchdog that he had declared the interest on the Ministerial Register and Greenberg concluded that he was satisfied that Sunak had confused the concept of registration with the concept of declaration of interests.

I formed the view that the failure to declare arose out of this confusion and was accordingly inadvertent on the part of Mr Sunak, noted Greenberg in his inquiry report released on Wednesday. In view of this, I decided to conclude my inquiry by way of the rectification procedure available to me under Standing Order No. 150, he said, which stops short of a formal report to be tabled with members of Parliament in the House of Commons to determine a course of action.

Under the requirements of the Standing Order, Sunak acknowledged and apologised for the breach of the rules. I apologise for these inadvertent errors and confirm acceptance of your proposal for rectification, Sunak wrote in his letter to the Commissioner. I welcome your confirmation that your investigation related to declarations of interests; there is no question that I correctly registered my wife's shareholding," he said.

"I am also grateful that during our helpful discussion, you accepted that my response during the Liaison Committee hearing on March 28, 2023 complied with the rules on declaration, given that at that time, I had no idea of the connection between Koru Kids and the Childminder Grants Scheme policy. It was only after the hearing that I became aware of the link, as set out in my subsequent letter to Sir Bernard, the Chair of the Liaison Committee, dated April 4, 2023," he said.

In his correspondence, the British Indian leader also noted that should such a scenario arise again, he acknowledges a duty to write to the committee after an appearance before a parliamentary appearance to correct the record.

"I accept and once again apologise that my letter to the Liaison Committee on 4 April 2023 was not sufficiently expansive, as it confused the language of registration and declaration," he said.

The issue had dominated the headlines in the wake of the Spring Budget in March, which included a pilot scheme of incentive payments of 600 pounds for childminders joining the profession, a sum that doubles to 1,200 pounds if they sign up through an agency.

Koru Kids was one of six childminder agencies in England listed on the government's website when the policy was announced, and Akshata Murty was listed as a shareholder in the most recently filed paperwork for the business on Companies House.

Asked at a Commons Liaison Committee hearing if he had any interest to declare when talking about how the policy was formed, Sunak said: "No, all my disclosures are declared in the normal way."