RISHI SUNAK is under investigation for allegedly failing to declare that his wife holds shares in a childcare agency which received help in the Budget.

Parliament’s standards watchdog opened the inquiry into the Prime Minister under rules demanding that MPs be “open and frank” when declaring their interests.

The probe relates to Akshata Murty’s shares in Koru Kids, a Downing Street source said.

As MPs returned from their Easter break, an update from parliamentary commissioner for standards Daniel Greenberg showed that he had opened the investigation on Thursday under the Commons code of conduct.

Mr Greenberg’s inquiry appears to centre on whether the Prime Minister should have declared the interest to MPs.

Downing Street said the Prime Minister would clarify how it was declared as a ministerial interest, rather than to the Commons.

“We are happy to assist the commissioner to clarify how this has been transparently declared as a ministerial interest,” a No 10 spokeswoman insisted.

Chancellor Jeremy Hunt’s Budget announcement included a pilot of £600 incentive payments to childminders joining the profession.

Koru Kids, which is one of six childminding agencies listed on the government’s website, described the new incentives as “great.”

The register of ministerial interests has not been updated for nearly a year, but Mr Sunak promised that a new list would be published “shortly.”

Deputy Labour leader Angela Rayner charged that the delay had “left a transparency black hole which is enabling the Prime Minister and those he has appointed to dodge proper scrutiny of their affairs.

“If Rishi Sunak has got nothing to hide, he should commit to publishing the register before May’s elections, so the public can see for themselves,” she added.