A former Home Office worker was today under investigation for "marrying" his daughter so she would be allowed to live in Britain.

Jelili Adesanya, originally from Nigeria, allegedly fooled immigration officials by faking a wedding ceremony. But it is claimed the marriage was a scam to get his daughter Karimotu Adenike a permanent right to remain in the country.

It is believed the pair, who are living in Dagenham, will then divorce. After this, Miss Adenike will re-marry her real husband, who is still living in Nigeria with their four children, and try to get them all visas.

The Home Office is investigating the allegations. It is claimed it was first tipped off about the scam two years ago but did nothing.

Until recently, Mr Adesanya, 54, who has lived here since 1976 and has a British passport, was working as an occupational health nurse with immigration officials at Gatwick Airport.

A whistleblower says he sent letters to the British High Commission in the Nigerian capital of Lagos and to the UK Border Agency to inform them of the fraud. Names, addresses, passport numbers and even a wedding photograph was supplied.

After there was no response, he sent emails to then home secretary Jacqui Smith and ministers Vernon Coaker and Phil Woolas on 1 February. But he still heard nothing back.

The source claims Mr Adesanya flew back to Nigeria on 29 May 2007 and held the bogus ceremony a few days later at a register office in Lagos.

"They paid people to attend the wedding so that the British High Commission in Lagos would believe it was genuine," he said. "The commission then gave Karimotu Adenike a two-year settlement visa in October 2007.

"On her settlement visa form, of course, she did not mention that she already had a husband and four children. The date of birth on her Nigerian passport is not her real date of birth."

It is believed Miss Adenike, who is in her mid-30s, added 10 years to her real age to shorten the gap between her and her father. Her settlement visa expired last month and she is now hoping to be given the right to remain. Mr Adesanya denied the plot and says he has never been questioned about it.

He said: "Married my own daughter? I have never heard anything like this in my life. I deny it. She is my wife, not my daughter."

Deputy chief executive of the UK Border Agency Jonathan Sedgwick said: "If we identify marriages which we believe are not genuine, we will prosecute."