Labour‘s ‘anti-corruption’ minister, accused with members of her family of taking billions in bribes, is set to be questioned by investigators in the New Year, The Mail on Sunday has learned.

City Minister Tulip Siddiq is being investigated over claims that she and four family members embezzled £4 billion through a nuclear power plant deal in Bangladesh.

The country’s Anti-Corruption Commission (ACC) launched its probe into Ms Siddiq, 42, last week, along with her mother, Sheikh Rehana Siddiq, 69, and aunt, Sheikh Hasina Wazed, 77, Bangladesh’s former prime minister, ousted after 15 years of autocratic rule.

The ACC was ordered to investigate by the country’s High Court, which heard claims that the minister and family members siphoned £4 billion from the Rooppur Nuclear Power Plant project through fake companies and Malaysian bank accounts into the UK and US.

Last week, after the Daily Mail broke the story, Labour party officials described the allegations as ‘spurious’, and said Ms Siddiq denies the claims, adding that no authority has so far contacted her.

But officials at the Commission told the MoS that a team led by five investigators are now gathering ‘documentary evidence’ relating to Ms Siddiq and others, and are likely to write to them within weeks for their responses.

The ACC is likely to send its letter to Ms Siddiq through the British High Commission in the capital, Dhaka, which will make a serving minister of the Crown the subject of a foreign criminal investigation.

Officials, who did not want to be named, said that once they receive responses, investigators will assess if they can issue First Information Reports against each one to a court.

Tulip Siddiq (left) at the Kremlin in 2013 with her aunt, Sheikh Hasina, and Russian president Vladimir Putin

An FIR would turn Ms Siddiq formally into a suspect, and give Bangladeshi police the power to arrest her.

An ACC official said: ‘The investigation is at inquiry stage. Once the inquiry is over, we’ll send letters to everyone. She [Siddiq] will be called to make a response.’

Akhtar Hussain, the director general (prevention) of the ACC, said the letters will give Ms Siddiq and family members ‘the chance to defend themselves’.

If Ms Siddiq – whose roles include stamping out fraud in Britain’s financial sector – does not co-operate, then she will undermine recent commitments the Government has given to the Bangladeshi authorities to help the them recover billions stolen by members of Hasina’s government.

City Minister Ms Siddiq is being investigated over claims that she and four family members embezzled £4 billion through a nuclear power plant deal in Bangladesh

In October, National Crime Agency investigators visited Bangladesh to ‘support’ its anti-corruption probes.

A Tory MP has written to the Parliamentary Standards Commissioner asking to launch a probe into Ms Siddiq over the allegations.

Labour said: ‘Tulip has not been contacted by anyone on the matter and totally refutes the claims.’