Updated

Newly discovered documents indicate that the British government concealed how often it administered so-called "virginity tests" to female immigrants hoping to enter the country in the 1970s on marriage visas.

The documents, unearthed by legal researchers Marinella Marmo and Evan Smith from Australia's Flinders University, showed that the tests — meant to prove that women coming into Britain to marry were virgins — had been administered more than 80 times.

Although the tests first drew condemnation in the late 1970s, the extent to which the practice had taken place was not clear until now. The British government had previously acknowledged only two cases, both done at Heathrow Airport.

"We were shocked to see not one case, but many," Marmo said Monday.

The government acknowledged that the documents were valid, but a spokesman for the U.K. Border Agency declined to address the larger number of cases reported by Marmo and Smith.

"These practices occurred 30 years ago and were clearly wrong," he said. The official, speaking on condition of anonymity in line with government policy, said Britain's policies now protect the rights of immigrants.

Marmo and Smith's research began in 2008 and was first published Monday in the Guardian newspaper.

The results show that 73 women underwent the tests in New Delhi and nine in Bombay at British embassies between 1976 and 1979. The alleged reason was to weed out bogus immigration claims.

The researchers said the discrepancy between their findings and the official tally makes it clear that the government, fearful of damaging its international reputation, had deliberately concealed the scale of the practice.

The documents "are quite revealing about the extent of abuse within the immigration system at the time," Smith said. "There were a lot of machinations to deny or limit what was made public about these cases, which lends credence to the idea that they knew it was something bad, that it was a gross violation of human rights."

The files, letters and exchanges — some typed, some handwritten, often with scribbles in the margins — contained telling references to a broader agenda to limit immigration, Marmo said, pointing to one note that read: "Let us not pretend we're not discriminating."

The researchers believe the government could issue a more assertive apology.

"We cannot change the past, but at least we can set the record straight and we can look each other in the face and tell the truth," Marmo said. "Say it happened. Say you're sorry."