Tulip Siddiq voluntarily referred herself to the independent adviser on the ministerial code, the prime minister’s spokesperson confirmed today.

The anti-corruption minister is alleged to have been involved in brokering a deal in 2013 with Russia for a nuclear power plant in Bangladesh.

Billions of pounds are said to have been embezzled in that agreement.

Siddiq’s aunt, Sheikh Hasina, was the PM of Bangladesh for more than 20 years. She is facing an investigation herself after being deposed last year.

Siddiq is now the economic secretary to the Treasury and therefore responsible for preventing corruption in UK financial markets. She has denied the allegations against her.

On Monday, PM Keir Starmer revealed Siddiq had referred herself to the ministerial standards adviser Sir Laurie Magnus during a wider press conference on NHS reform.

Starmer added that he had confidence in her and said she had “acted entirely properly”.

Starmer’s official spokesperson later told reporters: “I would never get into private conversations, but it’s very clear that it was the minister’s idea to self-refer.”

He added that Magnus would conduct a “fact-finding” exercise to see if “further action” was required, including any further investigation.

The spokesperson said the government would make the outcome known to the public, but declined to set up a timeline.

He said: “It will be conducted as swiftly as possible. It isn’t for me to place a timeline on an independent process.”

In her letter to Magnus, the minister said she had done “nothing wrong”.

Siddiq said: “In recent weeks I have been the subject of media reporting, much of it inaccurate, about my financial affairs and my family’s links to the former government of Bangladesh.

“I am clear that I have done nothing wrong.

“However, for the avoidance of doubt, I would like you to independently establish the facts about these matters.

“I will obviously ensure you have all the information you need to do this.”

Shadow home office minister Matt Vickers said: “It is disappointing that Keir Starmer has allowed scandal in his government to overshadow today’s announcement.

“There are clear questions for his friend and anti-corruption minister Tulip Siddiq to answer about allegations made about her.

“She must be held to the same standards as other ministers in his government, indications so far show that that may not be the case.”